A college professor is working on a long-term scientific experiment when a baseball comes through the window, destroying all of his glassware and spilling the fluids that the flasks and test tubes contained. The pooled fluids combine to form the (fictitious) chemical "methylethylpropylbutyl," which then covers a large portion of the baseball. The professor soon discovers that the fluid, along with any object with which it makes contact, is repelled by wood (cf. Alexander Fleming's serendipitous discovery of penicillin).
At a corporation's base on the Neptunian moon Triton, mercenaries are setting up a defense perimeter to try to hold off an unstoppable cyborg warrior. The commander, Nabel, seals himself inside the control room. The cyborg destroys the soldiers' tank and then attacks a helicopter—which crashes into the control room. The soldiers are killed one by one, until Nabel finally deactivates the cyborg with a remote control. The remaining corporate employees discover that the cyborg was created by company owner E.J. Saggs. Saggs arrives at the base just as the battle ends, and takes the remote from Nabel. He reactivates the cyborg and orders it to kill Nabel.
Jeff Peters (John Malkovich) is an emotionally repressed scientist who can't stand others because of their intellectual inferiority. He dreams of deep space exploration, which would be difficult because of the lack of human contact for long periods of time. He develops the Ulysses android (which looks exactly like him) for the purpose of space exploration, since an android would not be affected by the isolation.
A garbage can spaceship is seen flying near Earth. The same garbage can is then shown inside an antique shop owned by Captain Manzini. A boy named Dodger is being assaulted by four bullies in a park. Juice, the leader, steals Dodger's money and drops him in a puddle. Dodger goes to Manzini's antique shop where he works. Manzini takes Dodger's clothes and cleans them while warning him to stay away from the garbage can. Later, Dodger sees Tangerine, Juice's girlfriend, who seems to be the most compassionate one towards Dodger, and tries to persuade her to buy something. Dodger is attracted to Tangerine and covertly smells her hair while she is distracted. The other bullies enter the shop and attempt to rough up Dodger again, but he manages to outwit them. However, amidst the tussle, the garbage can is knocked over. The bullies then bring Dodger into a sewer, handcuff him to a rail, and open a sewage pipe on him. Dodger is saved by little mysterious people named the Garbage Pail Kids.
Lou Francis (Lou Costello) and Bud Alexander (Bud Abbott) have just graduated from a private detective school. Tommy Nelson (Arthur Franz), a middleweight boxer, comes to them with their first case. Tommy recently escaped from jail after being accused of murdering his manager, and asks the duo to accompany him on a visit to his fiancée, Helen Gray (Nancy Guild). He wants her uncle, Dr. Philip Gray (Gavin Muir), to inject him with a special serum he has developed which will render Tommy invisible, and hopes to use the newfound invisibility to investigate his manager's murder and prove his innocence. Dr. Gray adamantly refuses, arguing that the serum is still unstable, recalling that the formula's discoverer John Griffin was driven insane by the formula and did not become visible again until after he was killed. However, as the police arrive Tommy injects himself with it and successfully becomes invisible. Detective Roberts (William Frawley) questions Dr. Gray and Helen while Bud and Lou search for Tommy.
The Stooges are TV actors who are trying to sell ideas for their animated television show The Three Stooges Scrapbook. Unfortunately, their producer does not like anything. He gives the boys ten days to come up with a gimmick or their show will be canceled. In the meantime the Stooges lose their accommodation when they are caught cooking in their room because Curly-Joe turned up the TV-disguised refrigerator way too loud. The only affordable accommodation that will allow cooking is found in an advertisement in a newspaper. The home belongs to Professor Danforth (Emil Sitka) and it resembles a castle.
In 1958, the town of Centerville, Illinois was invaded by a race of aliens. The invaders could fire lasers from their eyes and hands and reduce humans to "crystallized" glowing blue orbs. They took over the form of the humans who were either captured or killed.
Flesh (Vince Murdocco) is kidnapped by cheerleaders from a world known only as The Strange Planet, after the men on their planet are rendered impotent thanks to the villain known only as the Evil Presence (William Dennis Hunt). The Evil Presence, who is in an unhappy relationship with Queen Frigid (Maureen Webb), soon learns of Flesh's arrival on the planet, and wishes to transfer Flesh's penis to himself, in order to make up for his own poor endowment.
Orville (Lou Costello) is the oldest orphan at the Hideaway Orphans Home. He accidentally winds up inside a truck heading to a top-secret laboratory, where he is placed under the guidance of lab worker Lester (Bud Abbott) to help load supplies onto a rocket ship. While on board with Lester, Orville hits the ignition button and the rocket blasts off, flying across the country to New Orleans, where Mardi Gras is in progress. They exit the ship and witness "hideous creatures", which are actually costumed celebrants, and conclude that they have landed on Mars.
Kenny Starfighter (Johan Rheborg) is probably the most hopeless student that the Hero academics of the galaxy has ever had. His parents Benny (Per Mårtenson) and Jenny (Sissela Kyle) are tired of paying for his studies and give him an ultimatum: Graduate or become a hairdresser at the family salon!
A future post-apocalyptic world is ruled by the good-looking people. A terrorist group of disabled people, who see themselves as mutants, take arms against their oppressors. They plan to rid the world of "beautiful people" and superficiality. They are very inept at what they do and mistrust one another. They assassinate body builders, massacre an aerobics class on live TV and blow up a sperm bank as part of their violent campaign.
For the plot of the film-within-the-film, see This Island Earth
The film opens with mad scientist Dr. Clayton Forrester, working from an underground laboratory, explaining the premise of the film (and associated TV series). Mike Nelson and the robots Crow T. Robot, and Tom Servo, along with Gypsy, are aboard the Satellite of Love high in Earth's orbit, when Dr. Forrester forces them to watch the film This Island Earth to break their wills; as per the television show, Mike, Crow, and Tom make fun of the movie as it airs.
Distinguished Professor Gordon (John Hoyt) explains that Earth is being tormented by periodic "sex rays" which send people into a sexual frenzy. When one of the rays hits the Ford Tri-Motor passenger aircraft carrying Flesh Gordon (Jason Williams) and Dale Ardor (Suzanne Fields), the pilots abandon the controls and everyone aboard has manic sex. When they finish, Flesh and Dale escape the imminent crash by parachute. They land near the workshop of Flexi Jerkoff (Joseph Hudgins), who has a plan to stop the sex rays at their source.
The film opens with Agent Pillbox (John Ritter) walking through a forest, when he is shot and killed by an unseen assassin. Pillbox had been engaged on a dry run for a meeting that was to take place with a group of aliens seeking to help humans eliminate a chemical that will end all life on Earth, which scientists accidentally dumped in the ocean.