In "The Grim Adventures of Billy and Mandy", we meet the idiot named Billy and the snotty girl named Mandy, who apparently win a bet with the Grim Reaper over a sick hamster, making him have to be their best friend forever! These adventures show how much they drive him crazy! 

This show started out as "Grim & Evil" which combined "The Grim Adventures of Billy and Mandy" and "Evil Con Carne".