It was speculated by Mike Tobacco that ancient man based the appearance and pranks (Albeit in a harmless manner) of human clowns, court jesters, etc... in imitation of the aliens, indicating that Klowns have visited earth from time to time throughout human history. He refers (by name) to the "Ancient Astronaut" theory in support of this idea. This theory is a popular pseudoscience that asserts man was visited by aliens many times in the distant past who shaped humanity's history and culture.
They kill humans for food, usually by drinking their blood and liquified remains out of cotton candy cocoons, (Similar to spiders feeding on captured prey), indicating they are liquivores. They also ate at least one dog, meaning that humans are not their only source of nourishment, though they may be their prefered prey. Also, notable is the fact that, not long after their landing, (and before they began their main attack), their cotton candy storage room was partially stocked, (at least two were humans and one was a dog, the contents of the others are unkown), meaning they had either landed elsewhere on Earth earlier or that they hunt creatures from other worlds as well. While they are killing for food, they also appear to enjoy it, often laughing and mocking their helpless victims. At several points in the film, they kill humans with no intention of eating them, such as running a driver off a cliff and melting a security guard with acid pies, giving evidence of their sadistic nature and cruel sense of humor.
The human race has always mistaken the Klowns for harmless, (if annoying), humans wearing heavy make-up and using bizarre behavior to mock people, but the Klowns' circus-themed tricks and costumes are really used to conceal their true motives, to kill and eat people.
Klowns show a wide variety of appearance and size, ranging from the morbidly obese Chubby, thin, human-sized Rudy, tall Slim and the diminutive Shorty. It is unknown just how large they can grow, but Klownzilla was at least fifteen feet high. Hair coloration varies wildly, but skin tone is invariably heavily powdered white, with conspicuous shades of red, purple, pink or blue around the mouth, cheeks, eyes and eyebrows. Their cheeks are hard-looking and thick, almost resembling painted door-knobs. A good way to distinguish Klowns from Clowns is that the mouths are always larger than a human's, with thick lips, and filled with sharp teeth. They also have pudgy hands with only four digits, three fingers and a thumb.
The Klowns, despite their comical appearance, are a highly intelligent species, having space travel, advanced technology, efficient tactical and military skills, their own language and a warped form of culture. They are capable of speaking English, and almost certainly other human languages as well, but rarely speak at all, even in their own language. They may be telepathic, as evidenced by the fact that Slim not only knew Debbie's name and location (they had apparently never even seen one another until that point), but also that she was waiting for Mike to return, knowing his name (and voice) as well. Jumbo knew Dave Hansen's name without having met him, either. Klowns either have a better understanding of science or more advanced biology (or both combined) than humans proving what we consider impossible to be possible for them such as creating shadows that are not flat, filling up a volume with a bigger volume, knowing peoples' names without given information, perfect voice imitation, and converting plasma to solid (laser from a ray gun into a thick giant balloon and a cotton candy cocoon).
Almost nothing is known of their culture, but they appear to be led by the largest, strongest (male) member of the troupe, as evidenced by their fear of / reverence for Klownzilla. They also appear to be dominated by males, with females having little or no power in their society. Klowns love colorful, festive and humorous architecture, devices and clothing, and clearly enjoy life, particularly enjoying the taking of other people's lives. Rudy demonstrated that the Klowns have their own language when talking to Spikey but Bibbo and Slim were seen speaking English to manipulate Debbie and another girl at separate times to open the door for them.
Klowns display superhuman, or possibly supernatural, abilities. To list a few examples, the child-sized Shorty was able to knock off a full-grown human's head with one punch, and he later fit his entire body into a pizza box. Slim was able to capture humans within a shadow puppet, transform them into living popcorn kernals, and jump a multi-story building, Jumbo was able to shed and regrow his hands in a matter of seconds, and it's indicated that he was able to walk across walls and ceilings as well. Many Klowns seem to move more slowly than humans, but this could be a way of prolonging the chase, causing more fear and panic in their prey. Some, like Chubby, are so obese that they can barely walk, much less chase down fleeing humans, which may be one reason that they use tricks and games to lure humans to them, where they can use their weapons to kill them with minimum physical exertion. Others, like Rudy, seem to move at an average human pace. They are incredibly durable, and are unharmed by being shot at close range, (unless it hits the nose), and being struck by speeding cars doesn't phase them at all. The only known weakness is the Klown's bulbous red nose, if it is destroyed, the Klown spins rapidly, then explodes into a shower of confetti.
The Klowns appear to reproduce using popcorn-like eggs or larvae, which rapidly grow into snake-like, voracious creatures resembling monstrous versions of the familiar Jack-In-The-Box, before becoming the more powerful adult Klown. It is unkown how long Klown Offspring take to reach adulthood, but they were able to grow from popcorn larvae into Jack-in-The-Box monsters in the short time it took Debbie to take a shower. It is also a mystery where, exactly, the popcorn larvae come from. It should be noted that when Slim used a shadow puppet to attack several humans, he turned them into popcorn, perhaps he was planning on creating more Offspring using the transformed humans. Also, at least two female Klowns were seen, indicating that Klowns may reproduce in the more traditional way as well. And, to add further confusion, The Big Top possessed an enormous popcorn machine, possibly an incubator.
Only two Female Killer Klowns, Daisy and Rosebud, were seen in the movie. They seemed far more amorous than murderous, and were more intent on making love to the Terenzi brothers than harming them. There is a great deal of speculation on the origin of the female Klowns, and it has been suggested that they are actually human women who have been transformed into Klowns, either simply for sex or as part of the Klown's reproductive cycle, or, perhaps, both. The basis for this theory is that Debbie and at least one other woman, (a man called the police station saying a Klown had taken his wife away in a balloon), were taken to The Big Top alive in balloons rather than killed outright like most humans, and female Klowns were only encountered near the end of the invasion, perhaps giving them time to transform. It's also possible that the females prefered to remain in the safety of the ship, that they are more peaceful than the males, or that only male Klowns are 'allowed' to hunt and fight, females being forced to stay home... Only the Chiodo brothers know for sure.
Most of the Klowns are morbidly obese, including Slim despite his name (although this is possibly a case of irony, considering that the Klowns are the villains of an ironic movie). Fatso got his name for being very fat. They all have very drooping faces, bellies all from being fat. This could be that their diet of dissolved human flesh mixed with sugar-coated cotton candy is highly fattening and/or they drink large amounts.
Weapons and Circus-Themed Customs
These are Klowns' famous circus-themed and magic tricks.
- Shadow puppet by Slim, which had amused a group of elderly people by the shadows of George Washington's crew crossing the Delaware River, an elephant, a dancing lady, a rabbit, and then a Tyrannosaurus Rex shadow puppet that swallowed up the humans, who then appeared in Slim's hands as popcorn.
- An Invisible Car was used by Slim to force a driver off a bridge.
- The Big Top was a spaceship that resembled an old-fashioned circus tent when in landing mode, and a spinning top or hot air balloon while in flight.
- Pies were long thought to have been part of the Klowns' annoying behavior in humiliating people, but they actually melt humans to the bone, as shown when Slim, Shorty, Bibbo, Rudy and Fatso threw pies at a security guard who tried to block their way into The Big Top. Some pies, however, are harmless and filled with cream, three such pies fell on the heroes at the end of the film. Unless it was just ice cream from the Terenzi Brothers' truck that landed on the heroes at the end of the film, then it is easy to deny that there are any pies the Klowns make that are not deadly.
- Balloon pooch constructed by Spikey which barks like a real dog. Spiky and Rudy followed the balloon pooch like a prison hound to track down Mike, Debbie and Hansen twice in the film.
- Squirting flowers by Jumbo, are a harmless prank in which a bouquet of flowers squirts out water at the victim. Curtis Mooney was sprayed with water by Jumbo as a practical joke, which made Mooney even angrier, leading him to arrest Jumbo.
- Klown Kar is an automobile that can carry at least 5 Klowns inside even though it seems far too small to fit all of them from the outside.
- Bicycle, a tiny training bicycle with two small wheels on either side of the rear wheel and several loud horns used by Shorty for transportation. It was destroyed by a cruel biker, angering Shorty, who then killed the bully.
- Peek-a-boo was being used by Jumbo to lure a little girl to him so he can kill her with his mallet.
- Giant Balloons were used by the Klowns to capture and carry off human women without killing them.
- A Paper Whistle, much larger than normal and ending in a grasping hand, was used by Jumbo to grab officer Mooney by the throat and either break his neck or strangle him to death.
- Ventriloquist dummy by Jumbo after he had killed Officer Mooney with his red/yellow colored blow paper whistle. Jumbo was able to make the dead Mooney speak in Mooney's voice though vibrations, and blood was painted onto Mooney to look like he had red cheeks and a mouth like a wooden puppet's mouth.
- Puppet Show, a play in a small booth using little hand puppets was used by Spikey to lure an unwary teen to his death.
- Krazy Straws were used by the Klowns to drink the liquified remains of their victims from within the Cotton Candy Cocoons.
- Cotton candy guns are the most common weapons seen in the film used by the Klowns. They are usually hidden under hand puppets. They were used to kill three people on-screen and several off-screen, possibly hundreds or thousands in Crescent Cove. The Killer Klowns quickly reduced the population of the town in the film, checking everywhere for victims.
- Cotton Candy, or, at least, something resembling Cotton Candy, was used to encase the Klown's victims, much like the cocoons spiders use to store their prey. Something within the substance liquified the victim's bodies, while the cocoons safely held the remains until they could be eaten.
- Cotton Candy Cocoon, Balloon-Holding Vacuum Cleaner, a colorful device resembling a parade float with a vacuum scoop on the front, it was used by the Klowns to vacuum up the cocooned victims quickly, (rather than carry every cocoon by hand to The Big Top), and also to carry the balloons with trapped human women.
- Popcorn Bazooka is a large gun equipped with with a popcorn popper that shoots popcorn onto a victim, the popcorn quickly grow into Klown Offspring. The popcorn actually chases the victim for several yards, even turning corners to reach them.
Effect on Humans
Humans rarely suspect that the Killer Klowns are dangerous until it is too late, which is a great advantage, allowing the Klowns to proceed with their genocide. Using physical force to knock down Klowns prove futile. The Klowns cannot be injured by humans using conventional means, it is almost impossible to inflict even minor injuries. The only way humans are able to kill them is by popping the Klowns' red noses, causing them to spin around in a green flash before exploding. Officer Hansen was the only human character who was able to kill any of the Klowns, (He killed at least four Klowns; Jumbo, Fatso, an unnamed Klown who had a yellow green afro, and Klownzilla). The Klowns are heavily armed with circus-themed weaponry and magic tricks, making them dangerous opponents for any human trying to stop them.
At the end of the film, it has been confirmed that the Klowns remain an unknown and unsuspected threat to the human race as a whole. The audience can only be certain that the heroes of the film are the only people who know that Klowns are indeed evil alien beings. The state police, called in by Dave, never met the Klowns themselves, they only saw the Big Top lift off and explode. But the rest of Crescent Cove's police department were aware that the town was attacked by clowns, although they might not be convinced that the Klowns were from outer space.