"Sweet Seymour Skinner's Baadasssss Song" is the nineteenth episode of Season 5. It first aired on April 28, 1994. The episode was written by Bill Oakley and Josh Weinstein and directed by Bob Anderson. The episode is the 100th episode to be produced.
Superintendent Chalmers fires Principal Skinner after a disaster at the elementary and Skinner re-enlists in the Army. Bart, feeling partially responsible for Skinner's firing, helps to get his old principal his job back.
It is show-and-tell day at Springfield Elementary School, and seeing how most kids have geodes or other random items, Bart brings his dog, Santa's Little Helper to school. Everyone is excited to see Bart's dog, but Santa's Little Helper shortly makes his way through the school vents, when he is put away in a closet. Groundskeeper Willie is greased up and sent inside the vents and retrieves the dog, but Superintendent Chalmers shows up, in detest after hearing about the dog. Shortly afterwords, he fires Principal Skinner on the spot, and Bart is guilty because of his dog.
Skinner rejoins the army, but manages to gain a friendly relationship with Bart, even going out to Luigi's to eat. During these events, Ned Flanders becomes the new principal, and is very lax with the rules. Due to this, the school breaks out in chaos and the kids vandalize, tag and even lock Martin Prince up in cage. Bart feels bad for Skinner, and wants to try to get Flanders fired. Superintendent Chalmers shows up to do another inspection of the school, and Bart convinces him to fire Flanders because of the chaos the kids can make with impunity. Chalmers then hears Flanders say "bless the lord" on the intercom, and because you're not allowed to teach religion in public school, Flanders is fired and Skinner becomes principal again. Skinner and Bart know they can no longer be friends now that Skinner is principal again, so they say goodbye and walk away, feeling good.