Wario Land 3: Part 44: The Frigid Sea (Green Chest)

The Scepter you picked up from the Cave of Flames' Gray Chest clears up the murky black water in three levels. In The Frigid Sea, the black water hides a doorway that you can enter, as shown at 0:55. In the next room, the Green Chest is above you and the Green Key nearby, but Wario’s water jump is too short to reach it. You must take the doorway beneath the Green Key to navigate around it. At the end of this route, a Switch Block freezes the water, allowing you to obtain the Green Key. You then return along the same path to thaw the ice and finally reach the Green Chest. The Frigid Sea's Green Chest treasure is a Magical Flame, though Wario has no container to hold it, risking burning his hands.