Insectoid Parasite

This is an unnamed species of sapient insectoid parasites which can attach themselves to the spine of a Human host and control it. Two of them hatched from meteorite eggs that fell on Earth in the early 21st century, and were hunted down by Grays.

Biology
They're insect-like creatures and have at least four pairs of legs, although only two pairs are used for locomotion. While they've been observed to hatch from egg-shaped meteorites, this isn't their actual form of reproduction, and it's possible that these eggs are more akin to cocoons that allow them to spread to other planets.

Once they find a suitable host, they attach themselves to the upper spine and sink their legs into the host's flesh to take over the host's mind and control the host's actions. Those who are host to these aliens need to consume raw meat, preferably from live prey. They produce screeching sounds to communicate. Those who have been infected long enough start to develop black veins. They may also become impregnated and later give birth to a whole litter of insectoids, which are born fully-developed and ready to find a host of their own.

Despite being fast and dangerous, these parasites are physically fragile. If taken by surprise, they can be removed by hand, and their bodies can be easily squashed or otherwise destroyed by Grays or Humans.

Culture and society
These parasites are a sapient species, as demonstrated by their intelligent behaviour (for instance: intentionally damaging Annabelle's weapon during combat), communication and cooperation with other members of their species. Their cooperative instinct is evidenced by the fact that a host who's already fed may offer a live victim to feed another. Despite that, they're hunted by the Grays, indicating that the two species may be inimical, and/or that the Grays may have reasons to want to prevent planets like Earth from falling victim to the invasive parasites.

It should be noted that the Grays don't hunt the insectoids directly, except as a last tactic. Rather, they prefer to abduct an individual from the planet in which the meteorite eggs crashed and implant these abductees with a mind-controlling device of their own. These individuals are then equipped with an energy blaster and returned to their world, where they start hunting down the insectoids and their hosts. The reason for this is not clear, although it's possible that the Grays prefer this method because the abductee will be more familiar with the planet's terrain, and to avoid drawing even more attention from the population.

Appearances

 * Gray Matter (2018)