The Key of B-Stl (also known as Sky Temple Key 2) is the second Sky Temple Key required for access to the Sky Temple in Metroid Prime 2: Echoes. In the Dark Oasis in Dark Agon Wastes, Samus must use a Power Bomb on a Denzium wall to reveal the room's namesake, a pool of Dark Water. In the water, Samus must destroy a Flying Ing Cache to reveal the Key. The Light Suit is necessary as it provides immunity to Dark Water and Ingstorm, which are present in the room.