Ridley (Metroid)
One of Adam's final missions to Samus is to finish off Ridley, whom Adam fears might be more dangerous than the Metroids if left unchecked, and claims Samus is the only one capable of stopping him. However, Samus later discovers his corpse after he is killed, having had his energy drained by the Queen Metroid on the Bottle Ship. His mummified corpse turns up again in "Metroid Fusion" on the BSL station, after having apparently been removed from the Bottle Ship by the Galactic Federation and placed in a sub-zero storage room for further research (potentially into further bioweapon applications). It is later infected by an X Parasite, allowing it to gain the ability to transform into Ridley's likeness, known as . Samus later defeats the Ridley mimic and absorbs its Core-X, regaining her signature Screw Attack. What was left of the cloned Ridley's remains were destroyed along with the X when the BSL station crashed into SR388.
Metroid: Zero Mission
Space Pirates attack a Galactic Federation-owned space research vessel and seize samples of Metroid creatures. Dangerous floating organisms, Metroids can latch on to any organism and drain its life energy to kill it. The Space Pirates plan to replicate Metroids by exposing them to beta rays and then using them as biological weapons to destroy all living beings that oppose them. While searching for the stolen Metroids, the Galactic Federation locates the Space Pirates' base of operations on the planet Zebes. The Federation assaults the planet, but the Pirates resist, forcing the Federation to retreat. As a last resort, the Federation decides to send a lone bounty hunter to penetrate the Pirates' base and destroy Mother Brain, the mechanical life-form that controls the Space Pirates' fortress and its defenses. Considered the greatest of all bounty hunters, Samus Aran is chosen for the mission.