The Grim Adventures of Billy and Mandy S07 E15 Billy and Mandy Moon the Moon

"It's Good Grim Fun!"

When Billy is sent to bed after playing with his Dr. Brainiac action figure, he wishes he had an adventure. He notices a strange light outside and wanders into a corn field to investigate; he encounters Sperg, and both of them got caught by a UFO's tractor beam. Inside the extraterrestrials decide to experiment on them.