The Grim Adventures of Billy and Mandy - Season 7 Episode 15 Billy and Mandy Moon the Moon
Overview: 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.