Crite

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

Origins
The Crites are from another unknown planet, and in the late 20th century, the last eight Crites were being transported to a prison asteroid for termination. There were ten Crites 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 Crites are officially recognized.

Description
The Crites 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 Crites 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, Crites are understandably much smaller than when fully grown, and their hair is significantly shorter. In order to grow to maturity, a Crite must feed at least once.

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

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

The Crites 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 Crites prematurely left a meal earlier can be explained by the Crites' eagerness to leave the asteroid to get to Earth for both a larger supply of food and to escape execution.

General
Crites behave mischievously, but have a vicious appetite that makes them deadly when hunting for food. Generally, Crites will attack in packs and one single Crite will initiate the attack, while others attack afterwards to bring prey down. In order to travel, Crites 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 Crite 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 Crites encounter more than one human, or they feel sufficiently threatened (such as a lone Crite encountering humans) they will generally shoot poisonous barbs that can knock out targets until the barb is removed.

Intelligence
In terms of intelligence, the Crites 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 Crites ended up trapped in a burning factory, they utilize a defensive mechanism in which the Crites combine into one single large Crite ball. This mechanism is used earlier in the film, although on a smaller scale, using four Crites. 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 Crite gets bigger (via eating), until it towers over the humans themselves. This might feature of advanced maturity, as young Crites do not do this.

Reproduction
Crites have to eat sufficiently before they lay eggs, but it is unclear how the Crites reproduce since it is never shown or discussed in the films. It has been said that it takes six months for Crite 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 Crites have specific sexes, or whether they reproduce asexually. One theory is that crites 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 Crites 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 Crites are of that category, since TerraCor is intent on retrieving the last Crite eggs.