mob upto vandalize or destroy a piece of proprty very bad with grafiti.
ay homie watch my back while i mob up this billboard.
To add members to, or become a member of, someone else's "mafia."
Originally just shorthand for joining/asking someone to join you in Mafia Wars, it now includes real life situations.
(1) Bob: Mob up! firstname.lastname@example.org
(2) Carl: Yo, those four guys have been messin' with us all night.
Dave: Well there's only the two of us, so if you wanna take 'em on, we're gonna have to mob up.