Pull-a-Karl 

To hit on and attempt to steal your friend's, or former friend's girlfriend. This kind of person will flirt, talk to nonstop, and basically do whatever it takes to try to turn your girlfriend against you.

Pull-a-karl:
John: Did you hear what Joe did?
Pete: Ya he pull'ed-a-karl and ruined tom and jess's relationship completely. Now Jess hates Tom cause Joe made shit up about him and told her.

Pull-a-Karl by LGXL December 16, 2008

pull a karl 

When you sneak up on a group of people and say nothing and just smile when the group notices you.

"Dude, where the hell did you come from??"
"I was always here. I can pull a karl."

pull a karl by ThEnz0 September 14, 2009