Someone (usually Michael S.) who enjoys needlessly pointing out logical flaws by responding to internet conversations (that they weren't originally included in) with copious amounts of obscure (or useless/stalkerlike) information
Adam: "yeah, according to this list, the **** champs are ranked 22nd...that can't be right"
Mike: (ignoring **** reference) BLAHBLAHBLAHBLAH I SURF FORUMS ALOT AND LEARN ABOUT OTHER TEAMS THAT I'VE NEVER TALKED TO NOR COMPETED AGAINST BLAHBLAHBLABLAH THIS IS WHY YOU'RE WRONG BLAHBLAHBALHABLAH
A: You're a killjoy.
Mike: (ignoring **** reference) BLAHBLAHBLAHBLAH I SURF FORUMS ALOT AND LEARN ABOUT OTHER TEAMS THAT I'VE NEVER TALKED TO NOR COMPETED AGAINST BLAHBLAHBLABLAH THIS IS WHY YOU'RE WRONG BLAHBLAHBALHABLAH
A: You're a killjoy.
by Pissedofffacebookguy February 27, 2011
by †wiligh† November 01, 2007
Im emo but in Gerard Way.And its 2017.Say a word and Im gonna shot you with my killjoy-dangerous-watergun.
by Ivexsis August 28, 2017
by Light Joker May 18, 2005
The killjoy tattled to the apartment manager, after he saw Mike enter his apartment with a gorgeous woman at midnight.
by Ronald Clifford Buckman August 09, 2003
When Bob walked in, and then everybody's expression changed and everyone stopped talking, Bob is a real killjoy
by Chieftawsmcool January 18, 2011