It concerns evil extraterrestrials that resemble clowns arriving on Earth and invading a small town in order to capture, kill and harvest the human inhabitants for sustenance.

[9] Just outside the Californian town of Crescent Cove, Mike Tobacco and his girlfriend Debbie Stone are spending time at the local lovers' lane when they witness the arrival of a strange glowing object.

Arriving to investigate for themselves, Mike and Debbie enter the structure and discover a complex interior with bizarre rooms, eventually realizing that it is the object and a spaceship.

They find the now-fleshless farmer encased in a cocoon made out of a cotton candy-like substance and are discovered by a Klown, which shoots popcorn at them from a bazooka-like weapon and then pursues them, aided by another one.

Narrowly escaping to the local police station, they report the incident to one of the officers and Debbie's ex-boyfriend, Dave Hansen, and his curmudgeonly partner, Curtis Mooney.

The duo then travel to the lovers' lane, only to find it abandoned and one of the cars filled with the cocoon's substance, proving the Klowns' existence and Mike's innocence.

Dave soon returns to the station and encounters the Klown using a deceased Mooney as a ventriloquist's dummy before shooting its fragile nose, which causes the alien to spin around wildly and explode into confetti upon its shattering.

Mike meets with his friends, Rich and Paul Terenzi, and, using the public address system on their ice cream truck, they drive around town attempting to warn people of the Klowns.

Mike, the Terenzi brothers and Dave witness Debbie's capture and give chase, following the Klowns to the local amusement park, where they have relocated their ship.

The Klowns' gargantuan leader, Jojo the Klownzilla, soon appears and destroys the truck, seemingly killing the brothers; Dave creates a distraction as Mike and Debbie escape before the ship begins to take off.

The Klowns' car then drops out of the sky and Dave emerges along with the Terenzis, the latter of whom miraculously survived by hiding in the ice cream truck's freezer moments before it was destroyed.

[10] The legs of the Klowns' sentient balloon animal dog were coated in latex by the film's special effects department in order to keep it from popping on the pine needles that covered the ground.

[10] Jojo the Klownzilla, the Klowns' gargantuan leader who appears in the film's climax, was originally intended to be created using stop-motion animation, but was instead portrayed by Charles Chiodo in a creature suit.

[10] In the film's original finale, Dave was killed in the destruction of the Klowns' ship, but this was changed after audiences in test screenings desired a more upbeat ending.

[15] However, in a 2023 Zoom Q&A at the Little Theatre in Rochester, NY, Stephen Chiodo said that the only things potentially reused were some ear props, with the resemblance in masks being purely coincidental.

[27] Charles Webb of MTV.com called the performances "a little rough", and wrote "If Killer Klowns isn't especially scary, it's only kind of funny but still gets by on the execution of extremely inventive visuals based on the clown/circus motif".

[34] The Chiodo brothers planned to release a "requel" (a portmanteau of remake and sequel), titled Return of the Killer Klowns from Outer Space in 3D, in 2012.

[36] In 2016 interviews, Stephen Chiodo stated that efforts to make further Killer Klowns productions had shifted, from planning one or more theatrical releases, to focus on television.

[7][8][38] On October 22, 2018, it was announced that the Syfy channel was in talks to license the rights to make one or more sequels to Killer Klowns from Outer Space, as well as additional movies in the Critters franchise.

[citation needed] John Massari, the composer of the synthesizer-filled score for the movie, rerecorded the music with a full orchestra at Warner Brothers Studios in 2016.

[43] On July 25, 2019, it was announced that the Killer Klowns from Outer Space scare zone of the previous year would be expanded into a full-fledged haunted house attraction for the 2019 event at both the Orlando and Hollywood locations.