Wario Land 3: Part 28: Bank of the Wild River (Gray Chest)

Another aquatic stage. You start next to the level's Gray Chest. The Gray Key is on the rightmost wall; pick it up and return to the chest, using the water current to help. The chest contains a Trident. Wario reads from the Yellow Book to cast a new spell with the Trident, summoning lightning that clears the river under The Big Bridge and creates The Steep Canyon.