The Ridley Robot is the final boss in Metroid: Zero Mission. The Ridley Robot is a Robot that Ridley made of himself. The Robot is incomplete, however. The Robot has not been introduced since Metroid: Zero Mission.
 Metroid: Zero Mission
After defeating Mother Brain and leaving Zebes, Samus Aran crashes back on Zebes. Her Power Suit malfunctions, thus forcing her to traverse this part of the game in her Zero Suit. After getting inside of the somewhat ancient Chozo temple, Samus recovers her Power Suit. After making your way throughout this part of the game, you run into a room and meet Robot Ridley. A fight ensues, and you have to take caution, because this form of Ridley is highly dangerous. It uses claw swipes, homing Missiles, and laser beams. There is a glass-encased panel on the Robot's chest. The panel resembles Meta Ridley's weak spot. Only shoot Missiles at it to break it, as beam shots have no effect. After defeated, a self-destruct sequence is initiated, and you have to race to a ship. You end up ambushing a few Space Pirate guards at the end of the trail, and you then hop into a Space Pirate ship. From here, you fly off, and your mission is complete. Then the ending credits play, and you get one of many pictures at the end showing Samus.