Ridley is a character from the Metroid series, and a major enemy in most of the games, generally acting as one of the later bosses. He is a space pterodactyl with vicious claws and large wings. His attacks usually include a charge attack, fireballs (a lot of small ones or a few big ones), a diving attack where he grabs Samus and damages her, and various moves with his tail, from slamming it on the ground to flailing it like a whip.
Ridley, whose "official" name is Geoform 187, is one of the main antagonists of the Metroid series, the other being Mother Brain. In spite of his bestial appearance and fearsome mannerisms, he is by no means a mindless animal, but a high-ranking Space Pirate General, sentient and capable of speech (although he only speaks in the comics).
Ridley is directly connected to Samus Aran's past and present. In the Metroid e-manga, he gained enough favor with the Space Pirates that he became one of their figures of highest authority. As such, he attacked and devastated three-year-old Samus's homeworld of K-2L in a raid for fuel and resources, and personally killed Samus's mother when she jumped in to protect her daughter. Unwittingly, he created his own worst enemy in Samus through this.
In Metroid and Metroid: Zero Mission he appears as the military leader of the Space Pirates and as a boss in the area with his name, and in Zero Mission the final boss is a robot in his likeness. He, his counterpart Kraid and all the Space Pirates desired to capture and clone the eponymous Metroid creatures for use in galactic domination. Ridley, however, was surprised to find the little girl from years ago, now a grown woman, having come to fight and kill him.
In Super Metroid, he kidnaps the baby Metroid that Samus found in Metroid II: Return of Samus. Driven by intense rage, Samus chases him back to planet Zebes, the Pirate base in Metroid and Zero Mission, and in the process of rescuing the baby Samus battles Ridley and the other Space Pirate leaders again, ultimately escaping the destruction of Zebes, which marked the final and true death of Samus' longstanding nemesis.
In Metroid: Other M, a clone of Ridley, from a DNA sample found on Samus' armor after the events of Super Metroid, is unintentionally cloned with the result being a small white creature called "little birdie", that Samus later encounters on the Bottle Ship. It evolves into a large purple lizard that ambushes Samus and then into Ridley in his most recognizable form. Samus re-encounters the reborn Ridley. Having thought she'd eliminated him permanently, his presence drives much shock into her that renders her unable to speak or move, until Anthony Higgs supposedly sacrifices himself trying to protect her, which drives rage into Samus again and allows her to fight and kill him again. Ultimately, heavily injured from the battle, he runs away, but is turned into a lifeless husk by the Queen Metroid on the Bottle Ship station.
In Metroid Fusion, the body of Ridley (presumably of his clone), cryogenically frozen, reappears on the Biologic Space Labs research station, which Samus encounters halfway through her mission there, to witness it shatter, while an X Parasite mimicking him exits the body. Samus later encounters the X-mimic, and she defeats Ridley, presumably for the final time.
Ridley appeared on Planet Zebes, flying in the background. His appearance is based off of his Super Metroid sprite.
Ridley has a cameo in the opening movie of Super Smash Bros. Melee, fighting Samus, when Samus jumps over him and shoots several missiles. As the opening movie was part of the game's initial reveal, this scene led to fan speculation that Ridley would be a playable character, though this ended up not being the case. Like in Super Metroid, Ridley is carrying the baby Metroid's capsule, though unlike in Super Metroid, Samus has both the Varia Suit and Missiles.
The head of the Space Pirates on Zebes, Ridley soars through space on wicked wings. Ridley may look like a mindless monster, but he's actually quite intelligent. After the SR-388 incident, where Samus captured the infant Metroid, Ridley took the Space Academy by storm, annihilating the complex and taking the Metroid back.
See also: List of SSBM trophies (Metroid series)
A remix of Ridley's theme from Super Metroid and Meta Ridley's theme from Metroid Prime both appear in Super Smash Bros. Brawl. In addition, Ridley's lair in the Metroid series, Norfair, is featured as a stage.
Hacking of Brawl's reveals incomplete Assist Trophy data for Ridley, though he is not available as such. Presumably, Ridley was initially planned as an Assist Trophy, but was instead included as a boss.
Role in the Subspace Emissary
The leader of the Space Pirates. He looks like a pterosaur but has high intelligence and a brutal nature. He plans to steal the baby Metroid from Samus for his own use. Ridley utilizes wings for a full range of flight and attacks with fireballs from his mouth and whips of his tail. As the culprit behind the murder of Samus's parents, the connections with Samus run deep.
See also: List of SSBB trophies (Metroid series)
When Sakurai first revealed the Pyrosphere stage for Super Smash Bros. for Wii U, he mentioned that a character from "Samus' past" may appear at any second. Furthermore, Ridley's shadow appeared on the stage in the April 2014 Nintendo Direct, in the section which discussed the Yellow Devil's role as a stage boss on Wily Castle. While some in the community were split on the subject of whether Ridley was actually a stage boss of Pyrosphere, or if this had been teasing of Ridley as a playable character in a vein similar to Palutena's prereveal teasing, Ridley ultimately appears as a unique stage boss, confirmed in the Super Smash Bros. for Wii U 50 Fact Extravaganza, over a year after the Pyrosphere was revealed.
In battle, Ridley will appear and attack players. Unlike other stage bosses, however, damaging Ridley enough will cause him to fight alongside the fighter. Damaging him enough after he joins a player's side will KO him, adding another point to the player's KO total, even if he is on the player's side. Ridley may gather energy under the ledge, transforming him into Meta Ridley. Curiously, his stock icon (used in the results screen) is of his Brawl artwork.
Ridley does not appear in any capacity in Super Smash Bros. for Nintendo 3DS, marking his first complete absence from any Smash title.
Ridley's physical appearance, like Samus and Zero Suit Samus, has been updated to match his appearance from Metroid: Other M.