Dark Samus

Dark Samus is the main antagonist of the Metroid Prime series. She was created after Metroid Prime merged into Samus Aran' Phazon Suit in order to survive.

Super Smash Bros. Brawl
In Super Smash Bros. Brawl, Dark Samus does not appear in a physical form, though she still has both a collectible trophy and a sticker. In Subspace Emissary, her sticker can only be equipped by Samus and Zero Suit Samus, and gives them an increase in their battering resistance when equipped.

Super Smash Bros. for Nintendo 3DS / Wii U
Dark Samus appears as an Assist Trophy in Super Smash Bros. for Nintendo 3DS / Wii U using her appearance from Metroid Prime 3: Corruption. She attacks using a variety of Phazon abilities, such as tentacles that sprout from the ground, a burst of pellets from her arm cannon, or spherical missiles that lock onto enemies. If enough damage is dealt to her, she staggers before disappearing; otherwise, she simply disappears after a period of time. Her appearance is also used for one of Samus' alternate costumes.