This huge, dragon-like creature lives in the depths of Norfair, deep below the surface of Zebes. Samus must traverse the dangerous, lava-drenched corridors of Ridley’s Lair before she meets up with this well-known miniboss. Ridley may not look too intelligent on the outside, but he is an extremely clever and vicious animal. Ridley has the rank of high commanding officer of the Space Pirate Army. Unlike the other hostile creatures that inhabit Zebes, Ridley is not under Mother Brain's control, but is acting out of his own free will to try and stop Samus.
Compared to the later games in the series, Ridley is an easy target. He never moves from his initial position, only jumping up and down while shooting multiple fireballs at you. The fireballs bounce when they hit the ground and move in a fairly predictable pattern. Ridley can be fought multiple ways, but there are two major strategies for his defeat. The first is to freeze his fireballs with the Ice Beam, after which Ridley will be unable to blow anymore. You can then jump over them and blast him away with missiles. The other method is to bring along the Varia and Wave Beam, jump directly into the dangerous liquid below, and move right underneath Ridley. Keep jumping and shooting upwards until he is defeated. Ridley rewards you with an upgrade of 75 missiles when he dies. You can then replenish your health with the Energy Tank in the neighboring room.
He is named after Ridley Scott, the director of the Alien movie franchise, of which Metroid draws its major inspiration from.
The instruction manual states Ridley is the original life-form of the planet Zebes, but this is probably no longer canonical. His original design was an odd, five-eyed chubby dragon, but all later incarnations are inspired by the sleek, saurian design from Super Metroid.
