Ridley is a dragon-like alien and is one of the main villains in the Metroid series of video games. He is directly responsible for the murder of Samus Aran's mother and partially responsible for the death of her father. Ridley also has an upgraded cybernetic version of himself named Meta Ridley. Aside from the Metroid series, Ridley has appeared in all three games in the Super Smash Bros. series, as well as in animatronic form for Nintendo Land.
 Super Smash Bros. series
Ridley also makes a brief appearance in the opening cinematic of Super Smash Bros. Melee, where he can be seen battling his archenemy, Samus Aran. A trophy of Ridley can also be obtained in this game.
In Super Smash Bros. Brawl, Ridley is fought twice in the Subspace Emissary. The first time, he is fought by Samus and Pikachu. As the two reach the exit to the facility that contains Samus's Power Suit, Ridley appears without warning and snatches up Samus. Roaring, he slams her into a wall and drags her along it. Pikachu comes to Samus's rescue, hitting the space dragon with a well-placed Thunder attack. The battle begins after this. Ridley fights similarly to Master Hand, using many brutal physical attacks. When he is defeated, he falls off the arena. The second time, he is fought in the Great Maze with any characters that have been rescued throughout the Subspace Emissary. He uses the same attacks and is defeated in the same fashion as in his first appearance.
Remixes of Ridley's theme music from various Metroid games can be optionally played in the Frigate Orpheon stage in Super Smash Bros. Brawl.
 Nintendo Land
Ridley first appears in the seventh level of the Assault Mission mode, Destroy 10 Cyclons. Unlike in its later appearances, the Ridley robot can't be defeated directly here, but it is possible to make it leave the arena by shooting all its weak spots multiple times. This however gives no reward and only makes the rest of the mission much easier as he will not disturb the player. Ridley later makes a proper appearance in the twentieth and final main level, The Final Battle. Here, Ridley is fought in three stages, in each of which the Miis must destroy targets on its chest, mouth, and tail. In the first set of targets, Ridley attacks by firing beams from its mouth and shooting its tail. The second wave adds a target on its right hand, which detaches from its main body and attempt to attack the Miis, as well as firing missiles at the Miis. The final part of the battle places one additional target on his left hand, which fire beams as well.
In the extra stages, Ice Ridley is introduced, but the normal Ridley makes another two appearances as well. In level twenty-eight, Ridley and Ice Ridley, the Miis must, as the title suggests, fight both forms of Ridley at the same time. Ridley appears for the final time in level thirty, The True Final Battle. As in its first appearance, Ridley cannot be defeated; it is merely a distraction for fighting the level's actual opponent, Kraid.
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