Someone who inserts themselves in a group of talkers for the soul purpose of causing terror and casualties by detonating with a poor choice of words to kill an entire conversation.
Also see: Conversation Insurgent
Guy 1/2/3/4/5: (Carrying on conversation of work, women, and sports)
Conversation Bomber (Guy 6): Guys, I'm gay! After all these years!
Guy 1: Dude, that chick is bangin'!
Guy 2: I'd do things to her that would make a hooker think twice.
Conversation Sniper: She's not bad, but I think I would want to talk to her for a bit before hand just so I know I won't be stuck with some weird girl for the rest of the night.