An Alaskan bull worm is a fictitious, animated animal from the second-season episode of "SpongeBob SquarePants" entitled "Sandy, SpongeBob, and the Worm." The creature is large enough to engulf the entire town of Bikini Bottom, and the town's residents try to save themselves by pushing the buildings out of the way while Sandy Cheeks and SpongeBob attempt to corral the giant worm.
The Alaskan bull worm starts the episode by eating Sandy's tail, a large portion of SpongeBob's house, the welcome sign to Bikini Bottom, some children's homework, a wheelbarrow and the butts of two fish. The town gets together to find a solution, and Sandy claims the job will be easy since she has wrangled bulls and worms in her native Texas. SpongeBob tries to convince her otherwise to no avail. Patrick suggests the residents move the entire town away from the worm's destructive path.
Upon finding the Alaskan bull worm in a cave thanks to "worm sign," Sandy ties it up in a knot, only to discover the purple thing is the worm's tongue and the huge cave is the worm's mouth. After a chase in which Sandy uses a lasso to save herself and SpongeBob, the huge monster plummets off a cliff and lands on the newly relocated Bikini Bottom, to which the Alaskan bull worm says "ouch."