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, Pakkun Flowers, 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.
Muda Kingdom 1
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 Question Blocks and a Brick Block. This place is guarded by two Honens. Next, the hero find a group of mountains, which contain coins and other two Honens. He leaves this location by two platforms mooving horizontally. Mario, then, arives in an island. This place contains a pipe that leads him to a bonus area, a Super Mushroom inside a Question Block and some coins, along them, there are some Honens jumping from the water in a bridge.
After passing through it, Mario finds a Bombshell Koopa, Goombos, Honens in mass and small mountains, linked by Used Block bridges. There is also a Question Block containing a star. Ahead, he 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 Brick Block disguised as a Question Block and some coins.
Mario reaches some bridges and two Yurarins Boos spitting fireballs. After them, the hero finds a Brick Block structure with coins inside it, which leads to the final area, where Mario can use a platform to reach two falling blocks, in order to get to the bonus exit.