Jazz

Aspiring rapper and mutant and drug dealer first appearing in Marvel Comics' District X comic (2004-2005). His real name is John Arthur Zander (JAZ—get it? Oh Marvel, you so cray cray!) and his mutant power was, seriously, having blue skin.

He gets killed in X-Men: The 198, issue 3 (May 2006). How sad is that? You get a lame-ass power, you don't have a real musical career (though he does have one in an alternative universe version of the character), then you get offed.