Ridley (リドリー) is a high ranking Space Pirate, the arch enemy of Samus Aran, and is one of the most common recurring characters in the Metroid series, appearing in almost every Metroid game, often encountered towards the end of the game. Ridley's appearance is considered similar to a skeletal pterodactyl with glowing eyes. Ridley is known for being very defiant and persistent; though Samus has killed him many times, he always finds a way to return, either through cloning or robotics.
- Normal (Metroid, Zero Mission)
- Meta Ridley (Prime, Prime 3: Corruption)
- Omega Ridley (Prime 3: Corruption)
- Organic Purple (Super Metroid)
- Clone (Other M)
- Ridley-X (Fusion)