Undertransit One is a room in the Dark Torvus Bog in Metroid Prime 2: Echoes. It serves as a transportation tunnel between Crypt and the Sacrificial Chamber. Like all underwater transit rooms in both Light and Dark Torvus, the room features a section that can be traversed with the Morph Ball. Two gears that do not run have an opening in the middle small enough for the Morph Ball to go through. The Aetherian version of this room is the Transit Tunnel West.