When an individual randomly exchanges a cute picture of their cat to another person. The person who recieved the picture of the cat is expected to send a picture of their cat. This process goes on and on until someone gives up. When one goes three days without sending a picture of their cat, they lose. If the other person does not own a cat, it is their responsibility to find one to take the picture of.
In the video game "Left 4 Dead", Catting is when somebody splits away from the team and runs for the saferoom. When somebody "Cats", they stop at nothing to make it to the saferoom. This includes disregarding fallen teammates, dodging Tanks, and hiding.
"We are getting swarmed back here! Save yourself and Cat it!"