Snapped: Killer Couples (2013)

S3E58 When Worlds Collide

Title: A Cosmic Encounter Plot: When Phineas and Ferb learn that a bizarre planet is on a collision course with Danville, they spring into action to prevent catastrophe. At the same time, Buford eagerly anticipates meeting the extraterrestrial inhabitants of the planet. On another front, Dr. Doofenshmirtz devises a scheme to pilfer the enormous ball of twine that the world cherishes.