The third level is the only place where Mario can use his submarine, the Marine Pop. The Muda Kingdom is mostly populated by seahorse-like creatures named Yurarins and Yurarin Boos. The boss himself is a large Yurarin Boo named Dragonzamasu, who shoots fireballs at incoming trespassers; it takes twenty torpedoes to defeat him. Common enemies here include the aforementioned Yurarins and Yurarin Boos, as well as Honens, Goombos, Piranha Plants, Bombshell Koopas, Mekabons, Gunions, and Torions. Tamao can also be found here, as the guardian of Dragonzamasu.
Mario's starting position in 2-1 and 2-2 inside the beam of the UFO makes it look like he beamed down from it.
This level is set in a beach-like area with many mountains. Mario begins in a solid soil area, under a spaceship. Ahead, he finds elevating mountains, two Mystery Blocks and a brick. This place is guarded by two Honens. Next, the hero finds a group of mountains, which contain coins and other two Honens. He leaves this location by two platforms moving horizontally. Mario then arrives in an island. This place contains a pipe that leads him to a bonus area and a Super Mushroom inside a Mystery Block and some coins. Along them, there are some Honens jumping from the water at a bridge.
After passing through it, Mario finds a Bombshell Koopa, Goombos, and Honens in mass and small mountains, linked by Empty Block bridges. There is also a Mystery Block containing a Star. Ahead, Mario finds a large path with hills, many Honens and a Yurarin Boo trying to attack him. Mario then faces a Piranha Plant in another pipe that leads to a bonus room and also some Goombos and a Coin Block disguised as a Mystery Block and some coins.
Mario reaches some bridges and two Yurarin Boos spitting fireballs. After them, Mario finds a brick structure with coins inside it. This leads to the final area where he can use a platform to reach two falling blocks, in order to get to the bonus exit.
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