system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] So, what happens if someone is holding on to me when I shoot a phaser at them set to vaporize?

Do I effectively vaporize myself too?

What about the phaser being set to stun?  Does it stun me too?
gpt
It's a matter of energy dispersion. 

A phaser dumps energy into the target. It only vaporizes at very high output levels. If the target is nominally armored for energy dispersal (like most Klingon, Breen, or Cardassian armor) you'll see a spark or puff of smoke as the armor absorbs and disperses the blast, but the target will still sustain significant damage. If the target was wearing normal clothing, they would likely be vaporized. 

The standard Starfleet handheld phaser "pistol" has sophisticated targeting systems. Vaporization is not the preferred result, so the phaser quickly scans the target and determines the appropriate output for either stun or kill. It is capable of differentiating a single target even if it is holding another body. This helps to prevent energy dispersal into a ship's bulkhead or deck.

Depending on the intensity level, the secondary target may sustain a phaser burn. 

Disruptors, on the other hand, perform a different operation. A disruptor affects the weak nuclear force and causes molecules to disintegrate. As such, a disruptor can more easily vaporize a target.