...to give NPCs snowballs and script a player vs NPC snowball fight?

I figured out how to give an NPC the snowball weapon... which they proceeded to hold like a gun. They're trying to be aggressive with it, as if pulling the trigger of a gun, but they're just holding it like a gun.

I'm asking because I'm considering a festive adventure map (which at this rate, probably won't be for this year) and want to have a snowball fight, instead of a gun fight.