TEXT: Mjölnir
  Weapon (warhammer), artifact (requires attunement)
  Mjölnir (pronounced myol-neer) is the hammer of Thor, the
  Norse God of Thunder. Often, Mjölnir is depicted in Norse
  mythology as one of the most powerful weapons ever created,
  "capable of leveling mountains." (Mjölnir - Wikipedia). In
  some stories, Mjölnir can only be wielded by a creature of
  good alignment, deemed "worthy" by Odin the All-Father.
  Magic Weapon. Mjölnir is a magic weapon that grants a
  +3 bonus to attack and damage rolls made with it. On a hit,
  the hammer deals an extra 1d10 lightning damage plus 1d10
  thunder damage.
  Random Properties. The hammer has the following
  randomly determined properties:
  2 minor beneficial properties
  1 major beneficial property
  2 minor detrimental properties
  Blessings of Odin. If you are attuned to the hammer, you
  gain the following benefits:
  You have immunity to lightning and thunder damage.
  You gain proficiency with History and Religion related to
  Norse mythology.
  Unless you or a high-ranking Norse diety such as Odin
  allows it, no other creature can lift Mjölnir or attune to
  Mjölnir until you become unattuned to it.
  Spells. The hammer has 7 charges. While holding it, you
  can use an action and expend 1 or more of its charges to cast
  one of the following spells (save DC 18) from it: call lightning
  (2 charges), chain lightning (3 charges), lightning bolt (2
  charges), shatter (1 charge), or thunderwave (1 charge). The
  hammer regains 1d4 + 3 expended charges daily at dawn.
  While attuned to the hammer, Thor or a follower blessed
  by Odin can cast each of the hammer's spells using 2 fewer
  charges (minimum of 0).
  Flight. While holding the hammer, you gain a flying speed
  of 90 feet. You cannot make attacks with the hammer while
  you are flying.
  Giant's Bane. Attacks made with the hammer against
  giants are made with advantage.
  Hammer Toss. You can throw Mjölnir, allowing it to make
  multiple attacks against distant enemies. As a bonus action,
  make a ranged weapon attack against a creature within 60
  feet of you. On a hit, the target takes the damage normal for
  Mjölnir.
  As a bonus action on your subsequent turns, you can move
  Mjölnir up to 20 feet and repeat the attack against a creature
  within 5 feet of it.
  You can continue to use Mjölnir like this for 1 minute, after
  which point it immediately returns to your hand. If Mjölnir is
  unable to return to your hand, it falls into the first available
  unoccupied space.
  You can use this property three times, after which this
  property can't be used again until the next dawn. In the
  meantime, the hammer can still use its other properties.
  Destroying the Hammer. The only way to destroy Mjölnir
  is by damaging it with an equally powerful artifact of Norse
  origin. Otherwise, only Odin or a creature blessed by Odin
  (such as Hela) can destroy the hammer, doing so at will. Until
  Ragnarok comes, Mjölnir reforms and regains its power in
  1d100 years.
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  Mjölnir | DMDave
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/5th Edition (5e)/3rd Party/DmDave/DMDave - Mjölnir.pdf