TEXT: d100: Interesting 
  Boss Mechanics
  
  08
  Players must ﬁght from the rafters above 
  a stage while trying to stop the villain 
  from sabotaging a performance going on 
  below.
  07
  There are ongoing rituals around the 
  area that must each be disrupted in a 
  speciﬁc way within the next few minutes. 
  Each completed ritual empowers the 
  boss with negative energy, escalating the 
  ﬁght and drawing the end times closer.
  06
  The boss fuses with slimes to become 
  bigger and stronger, but it can only get so 
  big before it explodes.
  05
  The boss is blind and takes damage when 
  hit by natural light. Adventurers need to 
  use the boss’s tremorsense/echolocation 
  to lead it into beams of light.
  04
  The boss cannot be close to an object or 
  another boss, or else it will rapidly 
  restore health; keeping it away will make 
  it easier to take down.
  03
  The room in which the boss is designed 
  like a long hallway. As the boss grows 
  weaker, they will run further down the 
  long room. Traps cover the room.
  02
  The boss will summon enemies that will 
  distract the players from the fact that the 
  boss is healing themselves.
  01
  This battle takes place in front of a 
  massive furnace. As the battle goes on, 
  the furnace gets hotter and hotter, to near 
  unbearable levels. Someone needs to 
  tend to the huge furnace while the others 
  battle to keep from melting!
  16
  The boss can only be killed by mortal 
  hands. Weapons, magic spells, and any 
  damage type besides ﬁsts/natural 
  weapons cannot damage the boss. 
  Immortals and gods cannot damage it.
  15
  The players enter a room with a button 
  and a locked door. If they press it, they 
  are all knocked unconscious and dream 
  about ﬁghting a boss 4-5 cr higher than 
  them. If they die in the dream they wake 
  up in the real world, and the door to the 
  next room is open. They can re-enter the 
  dream to h
  dream to help whittle away at the boss or 
  kill their friends to help speed up the 
  process of them getting completing the 
  dungeon.
  14
  The boss is in a gladiator style WWE 
  ring. Through some hints during the ﬁght, 
  the players realize that the boss isnt 
  actually trying to hurt them, and is 
  instead trying to make the ﬁght look as 
  ﬂashy as possible so that they can all 
  survive another day in the arena.
  13
  The boss is a lich who’s phylactery is a 
  bomb that would destroy the dungeon 
  and everything within a three mile radius. 
  Someone has to disarm the bomb while 
  the other pcs keep the lich busy.
  12
  The party ﬁghts a creature that can give 
  them a random disease if it hits them.
  11
  The villain casts a spell on the players 
  that makes them speak and describe 
  their actions in iambic pentameter. When 
  the villain dies they cry out saying “I am 
  slain!”
  10
  There is a massive mineﬁeld that has a 
  bloodthirsty invisible stalker roaming 
  around it. Mines deal heavy damage to 
  both players and the elemental, and 
  groups that can’t ﬁnd the stalker have to 
  activate the mines to either kill it or scare 
  it away.
  09
  The boss is in a sewer and monsters 
  were placed in the sewer to deal with 
  waste, but they end up attacking both the 
  players and the boss.
  A list of 100 diﬀerent mechanics to make your 
  big boss battles even more exciting. This list 
  was created by the community over at 
  www.reddit.com/r/d100. 
  100 Boss Mechanics
  d100      Trait
  INTRODUCTION
  
  32
  A mob boss that starts as several weak 
  combatants, but when one is killed the 
  survivors become stronger.
  31
  A half-dragon that gets an increasingly 
  powerful and large aoe attack at the end 
  of each turn, but loses his stacks when 
  knocked prone.
  30
  The boss tries to ﬂood the battleﬁeld with 
  an eﬀectively inﬁnite number of tiny, weak, 
  annoying baddies (bats, imps, mosquitoes). 
  They will simply keep coming even if the 
  whole cloud is killed. The sheer number 
  would be lethal if they weren’t driven oﬀ by 
  (light, ﬁre, sound, etc) Someone has to keep 
  the anta
  the antagonistic stimulus going during the 
  boss ﬁght and the boss targets the 
  blocker preferentially.
  29
  The boss is two deadly bosses 
  inseparably 
  inseparably glued back to back. Their 
  movement is halved/thirded. They are not 
  cooperating with one another. Only one of 
  the individuals is dominant at a time, the 
  other is dragged along. On their turn, roll 
  a d4. On a 1, the bosses bicker amongst 
  themselves and fail to take meaningful 
  action (ﬂip a coin to see if the dominant 
  action (ﬂip a coin to see if the dominant 
  individual changes). On a 2 or 3, both 
  bosses may attempt to attack a target 
  they are facing but do so with 
  disadvantage. On a 4, the dominant boss 
  may make an attack as normal, and the 
  subordinate one attacks with 
  disadvantage. If one individual dies or 
  becomes otherwise incapacitated, the 
  other is permanently dominant and 
  attacks as normal, but its speed remains 
  the same.
  28
  There are ﬂows of energy around the 
  room that heal the Boss if he stands in it. 
  You must knock him out of the ﬂows to 
  defeat him.
  27
  NPC has a mechanical limb that they 
  cannot fully control. It does the motion 
  for whatever he is thinking even if it’s 
  socially wrong.
  26
  Boss takes extra damage from opponents 
  who stand in a ﬂow of Necrotic/Negative 
  Energy. This causes the player to be 
  damaged too.
  25
  The boss is a support character. Most of 
  their goons are on the tanky side. 
  Whenever their goons drop low, the boss 
  heals them back up. The tanks protect 
  the boss as well.
  24
  The boss is aﬄicted with horrible 
  magical indigestion. Roll 1d4, on a 4 the 
  boss, instead of acting, groans and 
  releases a stinking cloud per the spell. 
  They are unaﬀected by their own stinking 
  cloud.
  23
  Boss contains a howling void. No verbal 
  commands or spells work. See if the PCS 
  can work with out speaking or writing to 
  each other.
  22
  A village has a pit of ghouls/zombies. 
  When a love one is dying they toss them 
  in to be turned. You have been tossed in 
  as food.
  21
  Boss is a keg golem. Body is mostly full 
  kegs. Some are ﬁlled with beer some are 
  wine. Players can target weak points like 
  corks or bungs to drain alcohol and 
  wound the boss. Once limbs and parts 
  are drained can be burned.
  20
  Boss is a wall, slowly shrinking the room 
  and pushing the party to a pit or wall of 
  spikes.
  19
  While walking through a cave they have 
  PCs have accidentally walked into the 
  open mouth of the boss. Tremors felt 
  during random ﬁghts of slimes and cubes 
  or small parasites eventually lead to acid 
  pools. Party can ﬂee or ﬁght their way 
  out. Possible risk of digestion if slow.
  18
  The boss is stationary in the center of the 
  room. When it receives enough damage 
  from one if the cardinal directions it 
  becomes invulnerable to damage from 
  that side, forcing the players manuver 
  around the room and minions to continue 
  damaging it.
  17
  The boss is a glass golem that can hide 
  and heal inside of mirrors. Players can 
  see the golem in the mirror, but must 
  break the glass to force it to come out.
  
  44
  A water elemental that heals to full health 
  after each round of combat from the lake 
  in which it resides. Deals AOE damage 
  equal to amount of health regenerated 
  (no other forms of damage output). Must 
  be burst to 0 HP in one turn or somehow 
  disconnected from the lake. (Maybe it’s 
  taunted or 
  taunted or charmed into leaving the lake. 
  Maybe the water is frozen or evaporated. 
  Maybe a bubble of air/wind surrounds the 
  elemental.)
  43
  Blind sorceress uses bird familiar to see. 
  When the bird is blinded, or taken out of 
  commission she will use AOE attacks in 
  an attempt to attack the party. If she has 
  allies, they may be caught in the crossﬁre. 
  If any of her allies are near her, they can 
  help direct her attacks but she won’t be as 
  accurate.
  accurate.
  42
  A gargoyle with a big scratch on it’s neck. 
  The gargoyle’s skin is tough rock, making 
  it immune to all but psychic damage, 
  unless the damage is applied to the tissue 
  under the scratch. A character can make 
  a CR 13 STR (athletics) check to keep it 
  open the bruise for one turn, which be-
  comes a CR 18 
  comes a CR 18 check if the gargoyle is 
  airborne. Another character can step in 
  to help, giving the strongest character ad-
  vantage in the check. Approximate CR is 
  5, two more than a normal gargoyle.
  41
  A cyclops that teleports 15ft back every 
  time it’s hit by an attack. The only way to 
  damage it is by using spells/ bombs that 
  aﬀect both spaces at once, stealth attack it, 
  or coordinate multiple attacks, so there are 
  players waiting to strike as the cyclops 
  teleports.
  40
  Strong ﬁghter type character with a great 
  sword that emanates magic power. Turns 
  out that he’s being possessed by the 
  weapon. When disarmed he won’t know 
  where he is or what is going on and 
  surrender immediately. Just make sure 
  that no one else picks up the sword.
  39
  A beholder that tries to argue that the 
  group will lose no matter what they do. If 
  a player argues with it enough, it enters a 
  ﬁt of rage. This makes strength rise, but 
  every other stat lower.
  38
  A goblin boss owns an army of 2D12 clay 
  golems. There is a large crack on the 
  back of each one.
  37
  An artiﬁcer that uses a set pool of arcane 
  energy (let’s say 100 mana) to power his 
  magical armor and wand. He uses 
  various spells, each of which take away 
  mana. His magical armor prevents 
  damage to himself at the cost of mana. 
  However, he can spend a turn draining 
  mana from other lifeforms (namely 
  players), so the trick with him is to either 
  break his gear directly, disable the 
  magi
  magical eﬀect somehow or run him out of 
  mana.
  36
  The Oracle had managed to somehow 
  imprison their (God/An
  imprison their (God/Angel), piercing their 
  immortal skin and chaining it up, leaving 
  the weeping deity of rebirth constantly 
  dripping blood. This Oracle uses magic to 
  manipulate this holy blood to instantly 
  heal any injury that they might sustain. 
  The secret to defeating her, however, is to 
  heal the Deit
  heal the Deity’s injuries, robbing The 
  Oracle of their crude immortality.
  35
  Some amorphous creature that is under 
  the permanent eﬀect of a mirror image 
  spell that refreshes after all images are 
  dispersed (which could be ﬂavored as 
  overlapping images of the same ﬁgure, or 
  many diﬀerent ﬁgures, like nightmares, 
  occupying the same space). The trick is to 
  use area of eﬀect sp
  use area of eﬀect spells, or somehow 
  marking the real creature on a successful 
  hit. For instance, striking the creature 
  with a dagger tied to an immovable rod 
  will pin down the real creature and pre-
  vent it from shifting around, rendering 
  the mirror mages useless.
  34
  A troll from Chult that was infused with 
  ﬁrenewt blood that gives it resistance to 
  ﬁre damage. Acid does normal damage 
  but no longer disables it’s regeneration, 
  only necrotic damage will stop it’s regen.
  33
  A Bugbear with armor covered in worth-
  less jewels he has glued and embedded in 
  his armor, knocking them out can be used 
  as a bargaining chip to pacify him from 
  attacking.
  
  57
  The boss gains resistance to a random 
  damage type for one round, every round.
  56
  The skeleton boss has no head of its own. 
  Instead it uses the skulls of others as a 
  substitute. When it wears someone else’s 
  skull, the boss gets all of their abilities 
  and their appearance. Taking enough 
  damage causes the boss’s current skull to 
  explode. The boss should cycle through 
  se
  several diﬀerent classes, helped by 
  minions bringing hidden skulls. 
  Eventually it runs out of skulls and 
  attempts to ﬂee, but like the proverbial 
  chicken with its head cut oﬀ, can’t tell 
  where it is going.
  55
  In the lair of the boss, everyone’s pockets, 
  bags, binders, satchels, cases, backpacks, 
  suitcases, luggage, etc become bitey mon-
  ster jaws. Attempting to retrieve an item 
  or spell component results in (1d4) of 
  damage with a risk of failure.
  54
  Each time you hit the boss, and it doesn’t 
  have temporary hit points, it gains 5 tem-
  porary hit point. Each time its temporary 
  hit points are depleted, the amount of 
  temporary hit points it gains from being 
  hit increases by 1. A hit that depletes the 
  temporary hit points grants a new set of 
  tempora
  temporary hit points after the remaining 
  damage has been subtracted from the 
  boss’s regular hit points. You want to use 
  as few and strong attacks as possible 
  against this boss.
  53
  A necromancer that rips the hearts out of 
  his acolytes, using them to a.) push thru 
  players, dealing dmg for each heart sent 
  and blooding the hearts b.) pull the hearts 
  thru himself to heal for the amount they 
  blooded c.) push/pull himself into position 
  by using the hearts as anchors.
  52
  The boss isn’t targeting the players, but 
  an NPC the players have to protect. Any 
  damage done to the NPC is passed on to 
  the nearest player.
  51
  The boss is a ghost, with a council of 3 
  individuals. The boss takes turns possess-
  ing each council member every few turns, 
  giving them new class speciﬁc spells.
  50
  Every turn, the boss teleports as a bonus 
  action. Everytime the boss takes damage, 
  it teleports to a random spot in the arena.
  49
  The boss has a mirror hidden somewhere 
  in the room. Anyone reﬂected in the 
  mirror takes half of the damage inﬂicted 
  on the boss. If the mirror is shattered, the 
  boss gains vulnerability to all damage.
  48
  The Necro-dancer. When confronted in 
  his dark lair, the lights suddenly go on, 
  revealing the room to be a massive dance 
  ﬂoor. At the start of each turn, “zone of 
  irresistible dance” is cast through 
  spea
  speakers that line the walls, which the 
  Necro-dancer has the remote to. Each 
  turn, the Necro dancer summons ‘backup 
  dancer’ skeletons, or something that 
  would be comparatively weak for the 
  part
  party’s level. This goes on until the song 
  ends, at which point a giant disco ball is 
  dropped from the ceiling with the intent 
  to crush the players, taking advantage of 
  the disadvantage dex throws and lowered 
  movement. After that, the dancers stop 
  being summoned, the zone of irresistible 
  dance does not 
  dance does not get cast again, and the 
  Necro-dancer is left all alone. The song 
  could also stop by breaking the speakers 
  or remote, or escaping the dance ﬂoor.
  47
  A boss that is vulnerable only if you can’t 
  see it. If someone is looking at it, it can 
  move around and can’t be harmed. 
  However, if no one is looking at it, its 
  movement speed slows to a crawl and it 
  is vulnerable. Cue everyone with their 
  eyes closed, swinging blindly around the 
  room!
  46
  A boss duo, with a big enemy who hits 
  hard and has a lot of HP, and a little 
  enemy who can hold his own, but mostly 
  assists the big enemy with healing. 
  Whenever the little enemy is attacked, the 
  big enemy goes crazy as a reaction, 
  dealing a ton of dama
  dealing a ton of damage, so the party has 
  to try and focus on the big one without 
  harming his buddy.
  45
  A drow beastmaster uses an owlbear to 
  destroy the group. The only problem is 
  that the creature is easily persuaded by 
  food.
  
  67
  Lights turn oﬀ on rounds 2, 6, 10, etcet-
  era and lights ﬂare on in a blinding burst 
  on rounds 4, 8, 12, etcetera and must 
  make a Constitution save to avoid being 
  blinded. Players can close their eyes to 
  avoid the blinding but make their attacks 
  with disadvantage that round.
  66
  BBEG has a lair full of deadly traps and 
  powerful minions, and always remains 
  one step ahead of the PCs. During the 
  ﬁnal confrontation, the BBEG is revealed 
  to simply be a clever and well-connected 
  commoner, completely unable to ﬁght 
  head-on with the party.
  65
  The Big Bad has powerful hexatic powers. 
  Every sixth attack heals her for twice the 
  damage dealt. The catch-it is any attack, 
  including a poke in the nose. Make sure the 
  characters can catch on to this one.
  64
  A baddie that gains new biological 
  growths every two turns. Starts at like a 
  CR4 with a bunch of health and eventual-
  ly could be over CR 20. Work fast or 
  PERISH.
  63
  The boss is a swarm of insects, nanoma-
  chines, magic particles, or something else 
  similar. It has a large pool of total hit-
  points, representing the amount of mass 
  it has, although this mass can be split 
  over multiple bodies. At the top of the ini-
  tiative round, the swarm can split into 
  smaller bodies or fuse with adjacent 
  bodies to form larger bodies. For exam-
  ple, for one round they may be a horde of 
  smaller, weaker creatures, and on the 
  next round they may fuse together to 
  become a larger and stronger creature. 
  The DM has a number of stat blocks pre
  pared for creatures this boss can form, 
  each of which has a minimum HP re-
  quirement to form. To make things more 
  interesting, there may be stores of addi-
  tional mass hidden around the battleﬁeld, 
  which the boss will attempt to reach to re-
  generate hit points and mass. If they want 
  to keep the boss down, the players will 
  have to stop any part of the boss from 
  reaching those stores of HP.
  62
  A massive pendulum in the lair reveals 
  the invisible boss when the weight is at 
  its height. The PC’s can attempt using 
  magic or physical means to hold the 
  weight up and keep the enemy visible. 
  The weight can also crash into the PC’s 
  or boss.
  61
  The bosses are a group of evil warrior 
  sorcerers that are exceedingly powerful, 
  however they become pained and 
  stunned whenever someone uses the 
  letter “z” in conversation.
  60
  The boss is hiding in the mouth of a giant 
  stone ﬁsh who can swim in the earth like 
  water. The ﬁsh can’t go outside a sphere 
  of a certain radius, but it allows the boss 
  to appear from the walls and ceilings and 
  try to smash people.
  59
  The boss asks the players campaign trivia 
  questions during the battle. If the players 
  answer correctly, the boss loses some hit-
  points. Answer wrong and the boss gets 
  to take an extra turn.
  58
  The boss alternates between attacking 
  and devensive modes. During attacking 
  turns, it gains +10 to all damage but has 
  -5 to attack rolls, can attack 3 times per 
  turn but takes 2x damage from all 
  physical attacks. After a certain amount 
  of hp has been depleted (up to the DM) it 
  switches to defensive mode. In this mode 
  it can’t attack or move, however it takes 
  1/4 damage from all physical attacks, has 
  a 1 in 6 chance to reﬂect all damge back 
  to the attacker and heals for Xd4 points 
  (where X is the number of pl
  (where X is the number of players it 
  faces) at the start of its turn. The 
  defensive mode lasts until it loses enough 
  hp (again, up to the DM) or it recovers 
  back to full health. It then returns to 
  attack mode. The golem had ﬁve stages, 
  each denoted by it losing a peice of 
  armour after each defensive stage was 
  ended by it taking damage rather than 
  healin
  healing. Each time if returned to attack 
  mode after losing armour, it’s AC was 
  reduced by 1 and its max hp by 20 but it 
  gained an extra +1 to attack rolls.
  
  76
  Boss has 99 copies of himself. A mob at-
  tacks the party, all identical. Roll d100 
  every time the party attacks. The boss 
  shares a portion of his life force with each 
  copy- when his copies are attacked, he 
  takes damage with resistance. When he 
  is attacked, he takes damage with vulner-
  ability. When he has lost a third of his HP, 
  and again when he has lost 2/3, a third 
  becomes illusory looking.
  75
  The arrogant yet naive boss is being 
  carried on a light palanquin by their 
  strongest and fastest minions. The boss 
  refuses to tou
  refuses to touch the the ground, as it is 
  demeaning … somehow more demeaning 
  than the minions tossing the palanquin 
  between them or using it as a blunt 
  weapon when convenient. The boss is a 
  powerful ranged attacker but spends half 
  their turns shouting confusing orders 
  instead of taking appropriate action. If 
  instead of taking appropriate action. If 
  the boss touches the ground, they have a 
  temper tantrum and launch a very strong 
  AoE spell at the party.
  74
  Every time the boss kills something, he 
  gains half its max hitpoints. He has a lot 
  of minions and will not hesitate to kill 
  them for a boost.
  73
  Boss is a low level mage with prototype 
  clones surrounding you. Whenever you kill 
  him, one of the clones wakes up, but gives 
  the mage unique abilities. One clone might 
  lower your AC for the ﬁght, one may have a 
  sneak attack and invisibility, another may 
  cast hunters Mark, and gain the scout 
  reaction to run when an ene
  reaction to run when an enemy gets too 
  close, all while retaining most of his spells.
  72
  Initially weak boss with lots of minions, 
  but as the minions die, buﬀ up the boss 
  bit by bit. Either the players press 
  through enemies to quickly kill them or 
  they cut through an army and ﬁght a big 
  old baddy.
  71
  A pair of sorcerers who are madly in love. 
  When the ﬁrst one is knocked out, the 
  other sorcerer, as a reaction, casts an in-
  credibly powerful spell at whoever took 
  them out.
  70
  The Boss is warded against blades and 
  anything with an edge does half damage. 
  Bludgeoning works as normal. Attacks 
  with wood items do double damage.
  69
  The boss has a stone that allows him to 
  polymorph at will. If the players steal the 
  stone, the boss loses the ability, but 
  whoever holds the stone is polymorphed 
  randomly every other turn. The Boss tries 
  to get the stone back.
  68
  Whilst the party is adventuring at sea, 
  their ship is beset by a dragon turtle of 
  legend named Kiirn. An intelligent and 
  greedy creature, Kiirn sinks ships for 
  their cargo which he then takes to his 
  nest in a cove on a nearby island. The 
  ﬁrst stage of the ﬁght takes place in the 
  sea with pl
  sea with players on a ship, which Kiirn is 
  attempting to sink. The captain of the 
  ship deems land the only safe haven and 
  heads for the nearest landmass, Kiirn’s 
  island. Along the way Kiirn may become 
  damaged enough to retreat, but the 
  Captain insists on landing and repairing 
  the damage. Otherwise, the ship becomes 
  damaged enough and sets oﬀ on a crash 
  course for the beach. The second stage of 
  the ﬁght is a scramble up the beach as an 
  angered Kiirn attempts to kill the party 
  and sailors. Players may stand and ﬁght, 
  attempt to rescue the sailors or ﬂee. Kiirn 
  attempt to rescue the sailors or ﬂee. Kiirn 
  is less concerned with the cargo than the 
  people at this point. The third stage fol-
  lows the retreat up the beach, a chase 
  through the rainforest on the island. The 
  players may chase Kiirn to ﬁnish him oﬀ 
  as he leads them to his cove, or Kiirn may 
  chase the players, angered by their 
  deﬁance and the damage they’ve done, or 
  perhaps angered that they escaped him at 
  the beach. The fourth stage is a ﬁght in a 
  large cave that leads to the cove. This is 
  the point at which players and Kiirn alike 
  are likely be exhausted and close to 
  death. FINISH HIM. At each stage, Kiirn 
  has a diﬀerent object
  has a diﬀerent objective which can vary 
  based on the player’s actions. You can 
  also spice it up with Kiirn having 
  something akin to lair actions in each of 
  the stages as well as environmental 
  opportunities.
  
  88
  The arrogant yet naive boss is being 
  carried on a light palanquin by their 
  strongest and fastest minions. The boss 
  refuses to tou
  refuses to touch the the ground, as it is 
  demeaning … somehow more demeaning 
  than the minions tossing the palanquin 
  between them or using it as a blunt 
  weapon when convenient. The boss is a 
  powerful ranged attacker but spends half 
  their turns shouting confusing orders 
  instead of taking appropriate action. If 
  instead of taking appropriate action. If 
  the boss touches the ground, they have a 
  temper tantrum and launch a very strong 
  AoE spell at the party.
  89
  A nearly impenetrable demon in a human 
  shell, covered in runic tattoos- but if you 
  land an arrow in the circle tattoo on his 
  neck it allows damage to hit the target for 
  the next 10 rounds or maybe however 
  long the arrow is on target. Possible 
  diﬃculty u
  diﬃculty up- he’s able to remove the 
  arrows by passing a strength save.
  87
  The boss is a corrupted holy artifact with 
  lots of HP. The artifact’s environmental 
  eﬀect causes the party to regenerate HP 
  and it also ﬁres healing beams. Healing 
  beyond a creature’s natural HP cap is 
  added as temporary hitpoints. If any 
  creature gains more than twice their HP in 
  creature gains more than twice their HP in 
  temporary hitpoints they die. Important 
  detail: the boss cannot beneﬁt from the 
  regenerative environmental eﬀect.
  86
  Torvin the Backbiter – He is a Dwarf 
  warrior who excels at disarming and 
  using his enemies’ weapons against 
  them. He starts unarmed and tries to take 
  the player’s weapons. If he succeeds and 
  makes a successful attack roll with their 
  own weapon, he deals automatic max 
  damage (or more, or less, depending how 
  you 
  you want to play it).
  85
  The boss is completely invulnerable. But 
  that doesn’t mean they are either physi-
  cally strong or able to avoid, say, being 
  locked up or captured. They just can’t be 
  physically hurt. Don’t give them spells or 
  ﬁghting ability more than a commoner- 
  just make them impervious to damage.
  84
  The boss is being healed by a certain 
  amount, let’s say 5dx per round (x going 
  up depending on how high level the group 
  is) because of healing crystals that are on 
  platforms that need to be climbed in 
  order to break. They each have a certain 
  HP, and after being destroyed they stop 
  healin
  healing.
  83
  The boss is protected by a shield that 
  reﬂects damage of the type last used to 
  hit the boss.
  82
  The boss can only be damaged the ﬁrst 
  time by each attack, after that the boss 
  becomes invulnerable to it until a they 
  have a long rest. The party must come up 
  with new ways to damage the boss. 
  (Switch weapons, new spells, etc.)
  81
  A crystal golem vulnerable to thunder 
  damage ﬁghts in a cathedral or other 
  temple. Nearby is a large bell or gong. 
  Attacking the gong converts incoming 
  bludgeoning damage to Thunder area 
  damage. Lure the golem into the area, 
  strike the gong – bingo.
  80
  A tall thin monk wanders a forest moving 
  with the sounds of nature and attacks 
  with capoeira. He gets +7 to dexterity 
  unless music with no rhythm is being 
  played. Then he gets -7 to dexterity.
  79
  A magic user ﬁghts with his pet wyvern. 
  The man is diﬃcult to hit due to a variety 
  of defensive and knockback spells such 
  as Wind Wall and Gust of Wind, while the 
  wyvern has naturally tough defenses and 
  resistances. However, when one moves 
  (including reactions), the other doesn’t. 
  Th
  They also share the same HP pool.
  78
  A massive Clockwork Golem that needs 
  to wind itself up every so often using the 
  wind-up key on it’s back. If it cannot, it 
  powers down and goes dormant until 
  wound back up again.
  77
  Two humanoids (Gladiators, Assassins or 
  Githyanki, for example, depending on the 
  CR you want) whose secret dream is to 
  be an animal. If you polymorph one of 
  them they stop being hostile, and the one 
  you didn’t polymorph will kindly ask you 
  if you can do the same to them. Then 
  th
  they’ll both leave peacefully.
  
  98
  The boss is wearing powerful heavy 
  armor that takes damage instead of the 
  boss, but makes the boss slow. As the 
  armor is attacked, it breaks oﬀ and leaves 
  the boss vulnerable, but the boss gets 
  faster and more maneuverable as a con-
  sequence. For each stage of armor that is 
  destr
  destroyed, the boss takes more damage, 
  the boss’s heavy attacks get weaker/fewer, 
  they become able to perform light attacks, 
  Movement Speed +, Initiative order +, etc.
  97
  A tall suit of enchanted armor that roams 
  the countryside, gathering corpses for its 
  necromancer master. It has an obscene 
  amount of health and CON and cannot take 
  damage from an attack that does less than 
  10 damage. A called attack to the head that 
  does more than 30 damage or a grapple 
  che
  check followed by a DC 15 STR check will 
  remove the armor’s helm from it’s 
  shoulders, causing it to collapse. An arcana 
  check will reveal that the armor is powered 
  by a small gem on the inside of its 
  forehead. A DC 19 slight of hand can 
  remove the gem.
  96
  A miniboss found in The Woods, a layer 
  of the Abyss run by Granny Gooseﬂesh, a 
  powerful Night Hag Sorcerer (the whole 
  plane is a dark and forbidding woods, 
  populated by dark versions of various 
  nursery rhymes and fairy tales): The 
  Piper is a powerful bard who summons 
  rat 
  rat swarms and sends them at the party. 
  When they ﬁnally catch up to him, he has 
  stolen and enchanted the children of a 
  village, and uses them as shields/has 
  them attack the party. The children don’t 
  do tons of damage, but they muck up the 
  battleﬁeld and are diﬃcult to ﬁght 
  (because they are little kids).
  95
  Lights turn oﬀ on rounds 2, 6, 10, etcet-
  era and lights ﬂare on in a blinding burst 
  on rounds 4, 8, 12, etcetera and must 
  make a Constitution save to avoid being 
  blinded. Players can close their eyes to 
  avoid the blinding but make their attacks 
  with disadvantage that round.
  94
  There are three bosses and each one 
  starts with an AC of 15. If the party kills 
  one of them, one round later the other 
  two’s AC jumps up to 25. If the party kills 
  a second one, one round later the last 
  one’s AC jumps to 30. The goal for the 
  party is to kill all three in one round by 
  pa
  paying attention to three glyphs on a wall 
  that display how close to death each boss 
  is by how brightly they are glowing.
  93
  The Midget Cultists of Oun-Bashon: A 
  group of gnomes or halﬂings who 
  worship a vile ﬁre deity. The party 
  catches up to them in a live caldera or 
  volcano. Each one is relatively easy to 
  beat, but they less attack and more 
  attempt to grapple and drag thems
  attempt to grapple and drag themselves 
  and the party into the live volcano, 
  seeking glorious martyrdom in the heat.
  92
  The bosses are a dark mirror of the 
  adventuring party from another plane. 
  One of the main questgivers actually 
  travelled from that plane to the adventur-
  er’s plane and gathered them together 
  because he knew they had great power 
  potential- since he knew of their evil 
  might. Make them twisted versions of the 
  characters, and have the player’s aid 
  come from good versions of baddies the 
  characters fought on their home plane. 
  For example- A gnome cleric was a war-
  lo
  lock, the ﬁghter was a death knight, the 
  wizard was an enchanter, etc.
  91
  Every round the boss auto-counters one 
  type of attack at random ever round until 
  the start of ot’s next turn.. Roll a d3- 1: 
  Melee 2: Magic 3: Ranged. If the boss is 
  attacked via melee, it will counter with a 
  melee strike, if the boss is attacked with a 
  ranged strike, it counters with a ranged 
  stri
  strike, etc.
  90
  The boss can hold a person with advan-
  tage by simply standing on that person’s 
  shadow. The boss has multiple spotlights 
  they can move around the battleﬁeld. 
  Although the boss cannot hold people on 
  a dark battleﬁeld, the boss has keen 
  darkvision.
  
  100
  A towering, ominous obelisk made of 
  steel is guarded by 3-6 Animated Armors, 
  3-6 Flying Swords, and 1-3 Helmed Hor-
  rors. The obelisk is covered in glowing 
  arcane sigils and scribbles that shine 
  brighter when the player’s step forward to 
  confront it, at which point the assorted 
  defenders m
  defenders move to attack. The obelisk 
  manifests a eye-like sigil which moves 
  around its surface each turn to channel a 
  beam that repairs and reanimates fallen 
  defenders. This beam causes the target to 
  regain 3d8 hit points as the components 
  are magically regrown and imbued once 
  more with magi
  more with magical energy, and is ﬁred 
  one time on each of the obelisk’s turns. 
  Any destroyed constructs hit with the 
  beam come back to life at 0 hit points and 
  regain the amount rolled for the beam. 
  To beat the obelisk boss, the invaders 
  may attempt to attack a construct target-
  ed by the eye beam while the ray is being 
  channeled, which causes the amount of 
  damage dealt to it to also go through to 
  the arcane entity within the obelisk. The 
  boss also takes 10 damage every time 
  one of the ar
  one of the arcane sigils or a signiﬁcant 
  part of a particular scribble is erased or 
  damaged in some way, whether the 
  marks are gashed deeply with a blade or 
  blotted out with a destructive spell. The 
  arcane entity within the obelisk has a 
  total of 80 hit points, AC of 15. Destroy-
  ing the obelisk entity makes it dissipate 
  into the surrounding area without a trace.
  99
  A singular Flesh Golem that’s body size 
  towers over any medium size creature. 
  The Flesh Golem’s skin has seen a 
  number of brutal battles, and has caused 
  it to become torn which a poor slave has 
  had to stitch up repeatedly after each 
  battle. The Golem often bleeds from the 
  stit
  stitches in combat ex-specially when the 
  beast takes ﬁre damage causing the crea-
  ture to take disadvantage on attack rolls 
  and ability checks until the end of its next 
  turn. The creature often leaves out a loud 
  roar when burned by any source of ﬁre 
  damage. Whenever the Golem’s hit points 
  fall b
  fall below 50% (207/18D12+90), any ﬁre 
  damage that the Golem is dealt is also 
  half and dealt to the Golem’s creator who 
  is within 90 feet of the battle.
  This list was created by the 
  community over at www.reddit.com/r/d100. 
  Put together by Casey Willis. See more at 
  www.dndspeak.com
  Special thanks to reddit users:
  u/dndspeak, u/budd
  u/dndspeak, u/buddychrist627, u/Woomy_Goomy, 
  u/Timjeface, u/redgriﬃn1, u/Pantaleon26, u/drew-
  cash83, u/CountofAccount, u/FickleFishy, u/Kiyo-
  hara, u/unspeciﬁedcarnage, u/The_Real_Gin-
  gasnappa, u/psdnmstr01, u/LeBlorqo, u/BrbShow-
  ering, u/anewlens, u/ezﬁ, u/SwansDontDie, u/the-
  brooksman, u/Courtholomew, u/LeBlorqo, u/Krip
  pner, u/Ramps_, u/who_wood, u/cfcsvanberg, 
  u/TomOnABoat, u/Nessius448, u/agreetedboat, 
  u/ShortChangeH3ro, u/Ayy_Johnny_J, u/Blossom-
  Samurai, u/marshmallow_ﬁgs, u/Pantaleon26, 
  u/Neonhilism
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SOURCE: textdata/thevault/Dungeons & Dragons [multi]/5th Edition (5e)/3rd Party/Casey Willis/100 Interesting Boss Mechanics.pdf