system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek/General] How would a phaser fare if used against a dragon?

We always hear about how tough the hide of a dragon is, but that comparison is almost always against magic or more primitive weapons like swords and arrows. So how would a phaser, or even just a regular gun with bullets work? Could you hurt or kill a dragon with either?

EDIT: Please address the question as it applies to both the "Stun" and "Kill" settings.
gpt
A regular knight's sword doesn't penetrate a dragon's hide, so it's stronger than steel. 

However, rifle rounds of 7.62mm caliber or higher can easily penetrate quite a bit of steel plating. The bad news is that their effect is rather limited on a massive creature such as a dragon, so killing it with a rifle or anything man portable would be like trying to kill a human by stabbing them repeatedly with a metal toothpick.

Phasers, on the other hand, melt and even disintegrate steel, and in fact, disintegrate anything that isn't durasteel, plasteel or other high-tech super dense materials. Unless there is some kind of magic involved, the dragon's hide and anything beyond it will be torn apart at the atomic level.

On the kill setting a phaser will at the very least remove a large portion of the dragon's body, probably resulting in death or outright disintegration, and a sufficient caliber firearm round will breach the hide and cause damage, but likely would require a massive amount of hits to score a kill.

Obviously any kind of bullet that would stun wouldn't be used on a dragon, so we're left with a phaser on stun setting. The phaser stuns by disrupting the normal transmission of impulses inside the nervous system of a living creature. Assuming the dragon's nervous system uses electromagnetic impulses to function, it's nervous system would be scrambled by a sufficiently powered phaser hit just as well as any other creature.

The problem would be how much energy you'd have to use to get the job done. Particularly tough humanoid races have shrugged off mini- and hand phaser shots, so a creature twice the size or more of a T. Rex would likely shrug them off as well. One would probably need a phaser rifle, phaser cannon, or several hand phasers draining their batteries in a continuous stream simultaneously in order to have any appreciable effect.