Dark Samus (ダークサムス, Dark Samus) is a character from the Metroid series. Originally appearing as a gigantic, heavily mutated Metroid that plagued Tallon IV alongside the very toxic mutagen called Phazon, Dark Samus is the primary antagonist of the Metroid Prime trilogy, and one of Samus Aran's greatest foes alongside Ridley and Mother Brain.
After making cameos as a trophy and sticker in Super Smash Bros. Brawl, and as a trophy and Assist Trophy in Super Smash Bros. 4, Dark Samus transitioned into a playable character in Super Smash Bros. Ultimate.
When Samus Aran defeated the titular creature of Metroid Prime, it took one last grasp at Samus and, in its seeming death throes, stole her Phazon Suit before it dissolved into a pool of Phazon. After Samus was forced to evacuate the collapsing Impact Crater, Metroid Prime had, unbeknownst to her, survived their battle. Some time afterward, the Phazon Suit's hand emerged from the pool of Phazon, albeit with clawed fingers and an eyeball on the back of its palm.
This effectively signaled the rebirth of Metroid Prime as a Phazon-based cyborg: the creature's essence and remnants of Samus' DNA within the Phazon Suit constituted its biological components, while the Phazon Suit itself constituted its mechanical component by becoming the creature's new body.
Thanks to these traits, the reborn Metroid Prime managed to acquire all of Samus' abilities, as well as human-level cognition. However, the creature was also obsessed with absorbing Phazon, a trait it retained from its time as Metroid Prime.
Dark Samus, as she would come to be known by the Space Pirates, is first seen by the Pirates in Metroid Prime 2: Echoes. They first believe she is Samus with a new suit and new goals, as she only steals Phazon the Pirates are mining on Aether for her own sustenance. Her actions later result in the Pirates' operation being discovered, leading to Samus' eventual arrival.
Dark Samus fights Samus several times across Aether, prompting the Pirates to consider an alliance with her, though this never occurs. Once Samus defeats the Ing and destroys Dark Aether, Dark Samus confronts her for the last time, but appears to disintegrate after losing.
After her defeat, Metroid Prime 3: Corruption begins with Dark Samus' remains being unknowingly collected by the Space Pirates as they clean up their Phazon mining operation, allowing her to reform. She absorbs all Phazon aboard the ship, and in doing so further develops her cognition alongside streamlining her Phazon Suit to a more mechanical, Light Suit-esque design. Thanks to her further developed cognition, Dark Samus corrupts the few Pirates she leaves alive into serving her and sets off toward her new goal: galactic conquest via the spread of Phazon across any and all planets she comes across.
Using the brainwashed Pirates, Dark Samus captures Aurora Unit 313, a Federation ship's organic supercomputer, and implants it into Phaaze, a sentient planet that is the source of all Phazon, in order to have direct control of the spread of Phazon. Dark Samus then proceeds to attack key Federation planets with Leviathans, sentient asteroids comprised of Phazon that will, in time, corrupt them into Phazon-based planets.
Although Samus manages to stop one of the Leviathans, Dark Samus arrives to infect her and three other bounty hunters (Rundas, Ghor and Gandrayda) with Phazon. The other hunters ultimately fall victim to Phazon corruption, thus forcing Samus to kill them in turn, as well as the guardians of each subsequent Leviathan. In the end, Dark Samus confronts Samus for the final time on Phaaze, first in direct combat and then after merging with Aurora Unit 313. In the end, Samus destroys 313 and, because of its symbiotic connection to both Dark Samus and Phaaze, definitively kills Dark Samus and renders any Phazon inert.
Dark Samus appears as a trophy and as a sticker. Additionally, a "Dark Samus" appears in Co-Op Event 7: Battle of the Dark Sides, though it is merely a blackened version of Samus and not the actual Dark Samus. It teams up with Dark Link against two players that play as their normal counterparts, with Link as player one and Samus as player two.
As an Assist Trophy
Dark Samus appears as an Assist Trophy in Super Smash Bros. 4. Unlike her trophy in Brawl, she uses her design from Metroid Prime 3: Corruption. Some of Dark Samus' attack animations are similar to Samus', such as her down tilt and her up smash. She hops around with long jumps, attacking with three different moves:
Before leaving, Dark Samus strikes a pose in which she holds her Arm Cannon in front of her face. Like several other Assist Trophies, she can be defeated if she takes enough hits. Upon being defeated, Dark Samus will disappear by fading out in a bright blue flash, similarly to when she is defeated in Metroid Prime 2: Echoes.
As an alternate costume
Dark Samus' color scheme is also the basis of one of Samus' alternate costumes. In the Galactic Avenger Event Match, this color scheme is used to simulate Samus battling Dark Samus. Similarly, the color scheme appears in the Final Battle Team-Up co-op Event Match that features several playable antagonists as opponents.
As a playable character
Main article: Dark Samus (SSBU)
Dark Samus appears as a newcomer in Super Smash Bros. Ultimate, and was formally announced alongside Simon, Richter, Chrom, and King K. Rool during the Super Smash Bros. Direct on August 8th, 2018. According to Masahiro Sakurai, Dark Samus and Chrom were included because of significant fan demand from overseas and Japan, respectively. Unlike in Brawl and SSB4, Dark Samus' design is a combination of her organic features and color scheme from Metroid Prime 2: Echoes and her redesigned Phazon Suit from Metroid Prime 3: Corruption.
As an Echo Fighter of Samus, Dark Samus is virtually identical in regard to function, although she does deviate from Samus in a few ways. As with other Echo Fighters, she has different animations, taunts, and victory poses (including a distinct victory fanfare). Unlike Samus, Dark Samus' rolls do not involve her transforming into a Morph Ball, but are compensated with slightly less ending lag. She also uses Phazon in her moveset, which is indicated by blue flames with the electric effect for all but two of Samus' respective flame-based moves, and dark blue energy for both Charge Shot and Phazon Laser (her version of the Zero Laser).