The Colossal Hole

The Colossal Hole is a level located in the east part of the Music Box World which appeared in Wario Land 3.It is only unlocked after Wario uses the three conch artificats to make the volcano erupt.

This is an underground level, it has some owls, UFO shaped like enemies and a thwomp like enemy. This level is unlocked along with The West Crater.

Grey Chest : Blue Snake Eye (right)
To get this treasure, Wario has to use his Puffy Form to get the key.He'll use the same technic for the grey chest located at the left side of the level.

After getting the two of the snake's eyes, the blue snake door will open in Tower of Revival.