Throughout the series, Ridley has undergone a variety of changes in appearance. In the original "Metroid" game, he was roughly the same size as protagonist Samus Aran and sported a more alien appearance (particularly in official artwork, which depicted him with eight eyes running down the length of his head and a small, lamprey-like mouth). His cybernetic form during the events of the "Prime" series is referred to as Meta Ridley and incorporates various ballistic weapon systems. A robotic duplicate, known as Ridley Robot or Mecha Ridley, appears as the final boss in "Zero Mission". In "Metroid: Fusion", he appears in the form of . "" showcases Ridley's life cycle, beginning as a small creature named Little Birdie that molts into a reptilian Mystery Creature before molting again into his adult draconic form.