X Parasite

The X Parasites, are the main enemy from Metroid Fusion. They are airborne, amoeboid parasitic creatures that can absorb a creatures DNA and become it. By absorbing the DNA, they also kill whatever creature they are copying.

The X come from SR388, the planet where Samus Aran exterminated the remaining Metroids. However, it turns out this act threw off the ecosystem of the planet. Metroids originally hunted the X so that they were not a threat to any life. With the Metroids gone, the X have grown rapidly absorbing DNA and killing creatures. Because Samus' suit in Metroid Fusion is fused with Metroid DNA, Samus can absorb X Parasites to regain health.

The X also have the unique ability to come together and form a bigger creature. One notable X creature is SA-X, an X clone of Samus's suit.