Turtle Zone

The Turtle Zone is a zone/world in Super Mario Land 2: Six Golden Coins. The zone consists of four levels, including the boss' level inside the whale, and a secret level from the submarine to the second floating island. The whale is not the boss, rather a level. Notably, the special world has a series of coins spelling "Mario Land 2", but Wario appears to have flipped the "M" upside down.