Crite

The Krites (mainly known as Critters) are a hostile hedgehog-like species from an unknown planet.

Origins
The Krites are from another unknown planet, and in the late 20th century, the last eight Krites were being transported to a prison asteroid for termination. There were ten Krites to be transferred, but two were killed as they were apparently eating everything in sight.

It appears they are an officially recognized species in the Intergalactic Council, as they have the reputation of making Intergalactic officials nervous because of their ferocity. They even have a policy on the extinction of any intergalactic lifeform, confirming that Krites are officially recognized.

Description
The Krites are small aliens resembling porcupines or hedgehogs. They have large rotund bodies, covered in a haze of black fur. Their stomachs were seen in their first sighting, but later sightings have shown they also have fur. They have small limbs, with tiny claws on both hands and feet. A prominent feature is their large mouths, which take up the majority of their face and are filled with multiple rows of sharp teeth, which they use to attack and devour prey. They lack any visible nostrils, but have a snout which is wide and flat, and they bear signature red eyes, which sometimes appear fluorescent from a distance. The Krites appear slightly larger in new sighting, and their fur appears more wild and spiky, as opposed to smooth, slicked back appearance when they were first spotted on Earth. The hair is generally black in color, but variations of brown and blue are not uncommon.

They've been described in various ways, such as being like rats, possums, Tasmanian devils, badgers and porcupines.

When first born, however, Krites are understandably much smaller than when fully grown, and their hair is significantly shorter. In order to grow to maturity, a Krite must feed at least once.

While individually fairly easy to destroy, in swarms, Krites can easily overpower adult Humans and Nothing Faces.

Diet
The Krites are notorious for eating almost everything in sight voraciously, but they are naturally carnivorous and prefer live meat.

The Krites have been seen eating electrical cables, stuffed animals, livestock, chickens and even a goldfish. These horrible little monsters have also seen eating a dog (as well as the dog food), wood, vegetables, the entire contents of a hamburger restaurant, and frozen burgers. They even feast on inedible things, like paint, mops, washing up liquid and even some of the materials in an experimental lab.

When eating a meal, they usually do not leave a meal unless they are threatened or disturbed by humans, as confirmed by Charlie, one of the humans to come in contact with them. The reason the Krites prematurely left a meal earlier can be explained by the Krites' eagerness to leave the asteroid to get to Earth for both a larger supply of food and to escape execution.

General
Krites behave mischievously, but have a vicious appetite that makes them deadly when hunting for food. Generally, Krites will attack in packs and one single Krite will initiate the attack, while others attack afterwards to bring prey down. In order to travel, Krites can walk, but will commonly tuck into a ball (like hedgehogs) and roll. They also have the ability to roll on the spot, gathering sufficient momentum to 'launch' from a position and reach quite long distances.

It would seem that the most unique Krite takes leadership of the group. It is usually the largest, but in other cases it's been one that's had its fur bleached, or another that had its head shaved bald.

If Krites encounter more than one human, or they feel sufficiently threatened (such as a lone Krite encountering humans) they will generally shoot poisonous barbs that can knock out targets until the barb is removed.

Intelligence
In terms of intelligence, the Krites are sapient, and are more than capable to work together in order to get to their prey. These beasts have once formulated a plan to gain access to a room through the ventilation ducts. Later on, they also deduce that they can use the elevator shaft in order to get to the humans near the roof. When the Krites ended up trapped in a burning factory, they utilize a defensive mechanism in which the Krites combine into one single large Krite ball. This mechanism is used earlier in the film, although on a smaller scale, using four Krites. It is very apparent that they can perfectly work a spacecraft and even maliciously destroy a farmhouse using the ship's weapons. These nasty creatures once rerouted a crew's ship to go to Earth, and they also utilize a growth accelerator in order to rapidly breed more offspring.

One particular Krite gets bigger (via eating), until it towers over the humans themselves. This might feature of advanced maturity, as young Krites do not do this.

Reproduction
Krites have to eat sufficiently before they lay eggs, but it is unclear how the Krites reproduce since it is never shown or discussed in the films. It has been said that it takes six months for Krite eggs to incubate, but this is contradicted by an instance when the eggs laid hatch within the space of only a few hours. It is also unknown if the Krites have specific sexes, or whether they reproduce asexually. One theory is that Krites are true hermaphrodites (being simultaneously fertile male and female at the same time). This would explain the rapid population growth displayed, since any mating would result in both individuals producing a clutch of eggs.

It can be assumed however that their fertility rate is high, given the large number of eggs present in the films. It can also be assumed that the Krites can self-replicate, since Dr. McCormack is heard explaining that TerraCor is in search of 'a self-replicating predator species' to use in their growth accelerator, and it is suggested that the Krites are of that category, since TerraCor is intent on retrieving the last Krite eggs.