Changes: The Big Prom: the Sex Romp: the Season Finale is the 13th and final episode of Clone High. It was written by Phil Lord and Christopher Miller. It originally aired February 10th, 2003.
Abe asks Cleo to the prom at the beginning of the episode, but seems to stutter between her name and Joan's. Gandhi attempts to get dates to the prom, but to no avail. Feeling glum, he approaches the "nerds" of the school and proposes that the make a prom posse, and that they all wear white tuxes. Joan comes into school with her new look, and after JFK asks her to prom, she accepts while putting on a fake "giggly slut" personality, hoping to make Abe jealous.
Abe and JFK both come to pick up Cleo and Joan, and Abe is breathtaken from Joan's appearance. When she and JFK approach their limo, Joan is displeased to see that JFK is also bringing Catherine the Great and the Bronte Sisters. Gandhi, along with Genghis Khan, Buddha, Van Gogh, Carver, Moses, Nostradamus, Issac Newton, and Thomas Edison, make their way to the prom, racing on the road with Jojo the Dog Faced Boy.
Meanwhile, Scudworth is preparing for the prom, hoping to be the prom king, after having painful memories of always being beaten by John Stamos. After he remarks that nothing could go wrong, Mr. Butlertron is fearfully reminded that The Board of Shadowy Figures told him that they were taking the clones on prom night.
Later at the prom, Abe tells Joan that JFK is a really lucky guy, hinting an attraction to her, after Joan is prepared for him to send yet another mixed message. Cleo then pounces on him and tells him it's "sex o' clock" and brings him to the meat locker. Scudworth is about to be crowned prom king, when Stamos comes in and is quickly crowned such. Abe and Cleo are about to have sex, when Abe, after hallucinating floating Joan heads on Cleo's breasts and crotch, realizes that he is in love with Joan and runs out.
Scudworth gets frustrated with Stamos when he is telling stand-up to the prom, and after Stamos offers him his crown, Scudworth stabs him in the eye with it, shocking everyone. Joan is outside, angry about Abe and her recent behaviour. JFK apporaches her and tells her that he likes her when she's being herself instead of a whore, and how Abe has bad taste in women. Abe runs to Gandhi and asks if Joan might be attracted to him, and Gandhi slaps him for ignoring the obvious. Gandhi then learns that Cleo is sitting naked and horny in her room, and tries to trick her into thinking he's Abe. After he fails, he runs into Marie Curie and apologizes for the way he acted, and they agree to be an abstinent couple.
The Shadowy Figure and his minions arrive, ready to take the clones away, and Mr. Butlertron hurriedly takes his vacation time. Stamos then distracts them by saying the prom king needs to lead a conga line (The Shadowy Figure's only weakness), and tells Scudworth to lead everyone into the flash freezer. After the conga line starts, Abe, Gandhi, Marie and Cleo all run into each other, and are shocked to encounter in the freezer Joan and JFK, in the bed, appearing to have just had sex. As the conga line also floods in and Joan stammers to the heartbroken Abe, Stamos pulls the lever to activate the flash freezer as Scudsworth escapes. Everyone becomes frozen, and as Abe tries to choke out his last sentence, it is interrupted by the freezing. The screen fades to black, saying "To be continued...?!"
- John Stamos as himself
- Tommy Walter as himself
- Standing on the Edge of Summer by Thursday (when JFK is hitting on the slutty Joan)
- Girls Singing by Mates of State (when JFK is hitting on the slutty Joan)
- Sunny Day by Abandoned Pools (during prom)
- Suburban Muse by Abandoned Pools (during prom)
- Never by Abandoned Pools (during prom)
- A Man Like Me by James Stuart (when Cleo and Abe are about to have sex)
- Blood by Abandoned Pools (during prom)
- Start Over by Abandoned Pools (during the conga line)