The Grim Adventures of Billy & Mandy

A Grim Surprise (1x14)

Air date: Aug 02, 2002

Billy tells Grim to help him throw a surprise birthday party for Mandy. Then, a reluctant Grim helps Billy prepare a cake while keeping it a secret from Mandy. In the end, a somewhat surprised Mandy reveals that her birthday isn't for the next five months, something that Billy already knew about.