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.