X PARASITE

The X Parasite is an alien creature found on planet SR388. An ectoparasitoid, it kills its host and absorbs its DNA and intelligence. This ability allows it to organically absorb and implement data, such as creating a heat resistant material to wrap itself in. It reproduces through a process similar to viruses, which makes it almost invincibly adaptable. When an X doesn’t come into contact with a susceptible host it stops growing and reproducing. It can stay dormant for eternities until disturbed.
Several organisms can laso gather to form a composite creature called a Core-X. Individuals can be forced out from a Core-X gathering.
They have one predator, the Metroid, genetically engineered lifeforms created by the Chozo to destroy them.
Source: Metroid Universe