Animal House

Dean Wormer places Delta Tau Chi on double secret probation because the fraternity is already on academic probation for poor grades and continual mischief. He works with Omega Theta Pi leader Greg Marmalard to find any pretext to revoke Delta's charter entirely, viewing the fraternity as a disruptive influence that threatens the college's reputation.

During a retaliation against the bullying of Flounder by Omega members, the Delta brothers orchestrate a prank that results in Neidermeyer's horse dying. This escalates the rivalry between Delta and Omega, adding a serious consequence to their ongoing conflict and giving Wormer additional justification to target Delta.

Bluto and D-Day steal the midterm answers from the trash, expecting an easy A. However, the Omega fraternity has anticipated this and swapped the real answers with fakes. The Deltas blindly study the incorrect answers, fail the exam spectacularly, and see their GPAs drop to dangerously low levels, giving Wormer the evidence he needs to threaten their expulsion.

Pinto brings Clorette to the toga party, and after she passes out, he helps her home, only to discover she is the 13-year-old daughter of Mayor Carmine DePasto. This revelation turns a reckless party decision into a potentially serious legal and political scandal that Dean Wormer uses to intensify his campaign against Delta.

Otter Stratton flirts with an older woman at the toga party without knowing she is Dean Wormer's wife, Marion. He carries on an affair with her, which later becomes another weapon in the administration's case against Delta, adding a personal dimension to Wormer's vendetta against the fraternity.

Greg Marmalard, leader of Omega Theta Pi, uses the kangaroo court to officially revoke Delta's charter and confiscate their house. This is the culmination of his plan to eliminate Delta, fueled by his girlfriend Mandy's affair with Otter and his desire to eliminate the rival fraternity that has humiliated Omega throughout the year.

After the charter revocation, Dean Wormer announces the Deltas' expulsion from Faber College and notifies local draft boards that all Delta members are eligible for military service. This represents the ultimate institutional punishment, threatening not just their education but their freedom and futures during the Vietnam War era.

With expulsion and the draft looming, Bluto rallies the remaining Delta brothers for a final act of rebellion during Homecoming. This desperate final stand is their way of resisting institutional authority and going out on their own terms, demonstrating the fraternity's defiant spirit until the very end.

D-Day converts the badly damaged Lincoln that the Deltas have been driving into an armored vehicle, hiding it inside a cake-shaped parade float. During the Homecoming parade, the Deltas unleash the vehicle as a weapon of chaos, using it to attack the reviewing stand where Wormer and Mayor DePasto are seated.

The Delta's armored parade float crashes into the reviewing stand, toppling both Dean Wormer and Mayor DePasto from their seats. The chaotic attack represents the ultimate symbolic victory against the institutional authorities who have persecuted the fraternity throughout the year.

Otter Stratton begins a secret affair with Mandy Pepperidge, who is Greg Marmalard's girlfriend and a member of the sorority Alpha Delta Pi. This betrayal within the Greek system intensifies the rivalry between Delta and Omega, providing Marmalard with additional motivation to destroy Delta entirely.

After their charter is revoked, Otter, Boon, Pinto, and Flounder steal a Lincoln and drive to a club where Otis Day and the Knights perform. When they realize the audience is predominantly African-American, tensions escalate and they flee amid vandalized cars and tense confrontations, highlighting the social divisions of the era.