Phrase derived from the popular game, Call of Duty 4 in which a team who were previously owned, opt out of the following round in fear of a subsequent defeat. They then lie saying 'We need to back out (leave current lobby) and get Karl' who is an imaginary player.
The phrase was originated when a group of players left a game in search of 'Karl'. Ten seconds later they rejoined, accidently, shouting 'Where's Karl?!' amongst laughter.
Use this a sneaky way of leaving a game without owning up to the fact that your opponents are too good for you.
This phrasing can be used in almost any online FPS game.
We need to get Karl?!
Lets back out and get Karl