Metroid Fusion

Metroid Fusion is the 4th chapter of the Metroid saga, in this one Samus Aran returns to escort a Science team to the planet SR388 where she gets unknowingly infected by an X parasite, virions that can replicate their hosts physical appearances and memories, killing them afterward. Whilst returning to B.S.L she loses consciousness and crashes her ship into an asteroid field. The Galactic Federation recovers her body and discovers that the X Parasite infected Samus's central nervous system. They counteract the parasite's damage by creating a vaccine using Samus's cellular sample from the remains of a Metroid that Samus previously contacted.

The vaccine cures Samus and also gives her Metroid-like characteristics, including the ability to absorb and use the nuclei of X Parasites for nourishment, and the Metroid's vulnerability to extremely cold temperatures. Her infected Power Suit is sent to the BSL station for examination.

The Federation then sends Samus back to B.S.L where explosions were reported only for her to encounter a new threat that will surely wipe all life from the universe if not stopped.