Any member in a collection of two or more people who is loud, annoying, large in stature (fat, heavy-set, morbidly obese), or far more expendable than any of the of members of the aforementioned group. Somebody who could be unquestioningly and unhesitatingly sacrificed.
As the group laughed at one another's jokes, one laugh rose above the rest in an obnoxious fashion, instantly pissing everyone off. Dirty looks were given, and as the reputable members of the group looked at each other, they could see the truth in their eyes. He was undoubtedly the designated sniperbait.