Billy is the titular central protagonist of the 2000 Cartoon Network animated TV series The Grim Adventures of Billy & Mandy. He is Mandy and Grim's best friend. He is a dim-witted, happy-go-lucky boy living in Endsville. He has an extremely low IQ of -5, having outperformed by even inanimate objects. Good-natured and incredibly dopey, Billy's curiosity tends to get him in trouble he can't get out of by himself. Billy enjoys the company of Mandy and Grim and would do just about anything for them.