The Killer Tomatoes are the chief antagonists of the sci-fi comedy series of the films, cartoons, and video games. They are (as the name suggests) tomatoes of a deadly and treacherous nature that seek to take over the world. The tomatoes have the ability to kill a human and are quite fond of doing so.
In the first film, Attack of the Killer Tomatoes, they do not have any mouths or even faces (which they had later on in the third and fourth films, Killer Tomatoes Strike Back and Killer Tomatoes Eat France) to eat humans. Also in the first film, the tomatoes have the ability to create explosions and roll quickly to chase humans and were giant in size, presumed to be that they grew from eating many humans. The U.S. Army launched a counterattack on the tomatoes, officially putting the country at war but the soldiers lose. However, they were defeated when the song "Puberty Love" was played, which was so horrible that the tomatoes shrink to miniature size and are squashed on.
The human characters in the films are depicted as being generally too weak to stand up to their tomato enemies, or just too stupid. One human, Sam Smith, disguised himself a tomato (very poorly, he only wore a tomato suit and didn't cover his face or hands) to camouflage in with the Killer Tomato army so that he won't get eaten. One night when the tomatoes are having hot dogs for dinner, Smith asks if someone can pass the ketchup.... then the tomatoes get angry and eat him up.
Although absent from the first film the mad scientist known as Professor Mortimer Gangreen would act as the creator and the caretaker of the Killer Tomatoes in the series following the 1988 film, Return Of The Killer Tomatoes.
In the original movie, no explanation is given to how or why the tomatoes became sentient and evil but in all future movies and cartoons they are genetically-altered by Professor Mortimer Gangreen as henchmen of sorts in his many evil, violent, and diabolical schemes.
The Killer Tomatoes were critically bashed, earning very negative reviews from critics, who agree that the K.T. movies suffered from low budgets and the films acknowledging how silly and nonsensical the writing and acting is wasn't enough to redeem the movies' creative quality.
The 1986 Killer Tomatoes video game has earned acclaim unlike the movie the game is based on.