Prom Night III: The Last Kiss

Prom Night III The Last Kiss is a 1990 horrorcomedy film that is part of the Prom Night film series, continuing the storyline involving the murderous ghoul Mary Lou Maloney. This is the only entry to depart from the strictly horror genre of the series, and is instead a spoof of the previous films. It was released in theaters on June 1, 1990. This film was followed by a third sequel, titled Prom Night IV Deliver Us from Evil.

Trying to go on with his life after dumping Mary Lou, Alex tries to patch things up with Sarah by asking her to the prom inaugurating the new gym, only to learn she is going with nerdy Leonard Welsh Jeremy Ratchford. Finding himself stalked by Mary Lou, Alex tells his best friend Shane Taylor David Stratton everything, which prompts Mary Lou to kill Shane by ripping his heart out. Shanes death is then blamed on Alex, who Shanes parents see fleeing from their house with blood on his hands. Tracked down to his house, Alex is arrested and put in jail. While in his cell, Alex is approached by Mary Lou who, after Alex rejects her once more, leaves to kill Sarah, electrocuting a pair of officers and leaving behind the keys to Alexs cell, which Alex uses to escape.As Alex races to the prom, forcing Officer Larry Brock Simpson to drive him there at gunpoint, Sarah is attacked by Mary Lou, who had killed Leonard by wrapping him in magnetic tape. Reaching the gymnasium as Mary Lou is about to kill Sarah on stage, Alex willingly goes to Hell with Mary Lou, making her promise that if he goes with her she will leave everyone else alone. As Mary Lou and Alex descend into the ground, Sarah follows them, jumping into the portal before it closes. Fighting off zombified versions of Shane, Leonard and Andrew in a nightmarish version of Hamilton High, Sarah tracks Alex down to Hells equivalent of Hamilton Highs gym, where Mary Lou is about to kill Alex so he can be her prom king for all eternity. ........

Source: Wikipedia