Assbutt

Assbutt is an insult formulated by Castiel.

History
Castiel first used this insult at Stull Cemetery. Upon arriving with Bobby Singer and a molotov cocktail filled with holy oil, Castiel shouted "assbutt" at Michael to get his attention, before tossing the molotov at him, causing him to suffer excruciating pain. Dean repeated the phrase out of confusion.

While in Limbo, Lucifer took Sam through memory lane and the two visited the exact moment at Stull when Castiel first shouted this insult. Lucifer admitted that he still didn't know what it meant.

Upon arriving at Limbo along with Dean, Castiel shouted "assbutt" again, but at Lucifer himself as a way of announcing his presence.

While confronting Lucifer at Club Meteor in Los Angeles, Castiel shouted "assbutt" to attract Lucifer's attention away from Sam and Dean, before attacking Lucifer using a guitar.

Appearances

 * Season 5
 * Swan Song
 * Season 11
 * The Devil in the Details
 * Season 12
 * Rock Never Dies

Trivia

 * The exact meaning of this insult has never been explained on-screen.