Bart suspects a rat in his circle of friends when all of his pranks backfire. Meanwhile, Homer grows attached to his rental car, which he gets to drive for a week while his old car gets repaired.

!! Tropes:

* BaitAndSwitchComment: When Bart reunited Nelson, Milhouse and Donny to talk about the rat, his comments suggested he figured out Donny was the one but he suspected Milhouse.
* ChekhovsGun: Bart's Blue Vines.
* DisproportionateRetribution[=/=]{{Jerkass}}: Skinner and Chalmers want to send Bart to the toughest juvenile detention facility they can just for a few mostly harmless pranks that Bart pulls and Skinner laughs when he causes Bart to be manipulated.
* TheMole
* TooDumbToLive: Given that Donny was new to the organization, it should have been obvious that Donny was TheMole, but Bart somehow instantly assumed it was Milhouse.
* WeatherManipulation: Homer triggers a thunderstorm '''''inside the rental car''''' by having the vents on the driver's side put out heat, and the vents on the passenger's side put out air. At Bart's request, Homer turns on the rear window defogger, which triggers '''''a small tornado!'''''
* WholePlotReference: To ''Film/TheDeparted''.