Ridley (Metroid)
Ridley returns in his Meta form once again in "", where he, along with the Space Pirate legion under his command, are corrupted by Dark Samus. He encounters and battles Samus on Norion, a Galactic Federation-occupied world, and the two fight while free-falling down an air shaft. Ridley is later supercharged with Phazon, becoming "Omega Ridley", and is charged with guarding the Leviathan Seed on the Space Pirate homeworld. He is confronted once again by Samus, and despite being defeated, he survives the fight and is later cured of his corruption after Dark Samus' defeat later on. Between the "Prime" trilogy and "", the Space Pirates reorganize on Zebes and hatch another plan to clone and weaponize the Metroids, while Ridley gradually begins to regenerate from his past injuries, gradually shedding his cybernetics. In the remake of the second game, "", Ridley, in his semi-regenerated form of "Proteus Ridley", attacks Samus on SR388 to steal the last remaining Metroid. Samus and the baby Metroid work together to defeat Ridley.
AM2R
The Metroids the player fights have four main evolutionary stages – Alpha, Gamma, Zeta, and Omega – which have been altered compared to their "Metroid II" counterparts, including new techniques used in battle; Alpha is the least altered, having only been given a new dodge move, while Omega has been altered the most, having been changed to earth-bound enemies that trap the player. The player confronts these Metroid bosses often and has to defeat 55 of them. Among the newly added bosses are non-Metroid enemies such as a moving statue.