Simpsons Season 5, Episode 19: Sweet Seymour Skinner's Baadasssss Song

Bart accidentally gets Principal Skinner fired after he brings Santa's Little Helper to school for show and tell. Bart feels guilty for what he did, and befriends Skinner. Meanwhile, Ned Flanders is hired as principal and the school goes to pot. Bart decides that while he enjoys having Skinner as a friend, he needs him as an enemy, but discovered that he returned to the Army to be a sergeant.