A smiley face with an asshat. It can be taken various ways. Most often used as a happy and silly expression. But other times it can be taken as an offense, calling someone an asshat. Lastly it is sometimes used to make a person feel better about themselves when someone complains at them for something they did.
1. Bill: Dude I won the internetz!
2. Bill: I cheated with your girlfriend.
3. Bobby: cheated on my girlfriend? You bastard!