"ate it", "fucked it", "pipped it", "finished it", "smashed it", or "Did a great job".
I killed it last night.
I killed that dish.
I killed my set.
I killed that pie.
I killed that girl.
That food was so good that I had to kill it.
My job was on the line. I had to kill it.
Killed it.
This game is great! I'm killing it.
The act of 'killing it' would be performed after a joke is being told when everyone has just got done laughing and 'the killer
tries to be funny and adds on to the joke in attempts of making it funnier. This of course is not funny, and in turn, 'the killer' was just a big buzzkill, otherwise known as 'killing it'
Person 1: Dude, Blake thinks he's so funny but no one ever laughs at him...
Person 2: Seriously, he tries to make everyone laugh, but all he's doing is killing it.