Wario Land 3: Part 97: Sea Turtle Rocks (Blue Chest)

Wario picks up the Night Vision Scope from the Green Chest of The East Crater. At 0:30, the scope is used in the tunnel room, revealing a new doorway. In the next room, he rides carts while avoiding lasers, which leads to the Blue Key and then the Blue Chest. The Blue Chest contains the Full Moon Gong. When Wario rings the gong, a full moon appears above the clouds. Playing the level at night will let you see the moon, and the gong is the level's final treasure.