Lulzkiller 

Someone who ruins a perfectly good 'your mom' joke by bringing up the fact that their mother is dead and therefore spawning an awkward silence.

Me: So does your MOM.
Guy: My mom's dead.
Me: Jackass Lulzkiller...

Lulzkiller by EpicFailJem March 31, 2009

lulz killer 

A common term in both internet and RL conversations. Someone who's sole ambition in life is to stop others from getting lulz or sometimes even epic lulz; often an internet user in a postion of power who tries to stop lulz-worthy acts of anarchy.

Person 1: WTF? Some n00b mod on wikipedia reverted my lulztastic edits to this page.
Person 2: What a Lulz Killer
--
Person 1: ZOMG this admin disabled my uber CS hacks; now I'll have to get headshots using only skill.
Person 2: o_O What an EPIC Lulz Killer

lulz killer by Master. A. N. Onymous January 11, 2009

lulz killer 

One who has killed a mass of lulz over an extended time period. Also one who stops lulz from occuring by not showing up where lulz occur.

Sean: Dude I asked Brian if he wanted to play CS with us after school.
Kareem: What'd he say?
Sean: He wants to hang out with his girlfriend instead.
Kareem: What an epic lulz killer.

lulz killer by Vaginabuttfarts February 24, 2008