Metroi Fusion (メトロイドフュージョン, Metoroido Fyūjon?) is an action-adventure video game developed by Nintendo R&D1 and released for the Nintendo Game Boy Advance. It is the fourth main installment released in the Metroid series. Metroid Fusion is centered around Samus Aran, a famed galactic bounty hunter, who is forced to battle legions of parasitic creatures aboard a space station.