Eely-Mouth

Eely-Mouth is an eel that appears only in Super Mario Sunshine. It lives in a massive underwater chamber below Noki Bay, and its gingivitis caused the widespread pollution in the area. In order to purify Noki Bay's water, Mario must clean Eely-Mouth's eight teeth, three of which are rotten and fall out after being sprayed with F.L.U.D.D.'s water. One of its teeth is revealed to be golden once it is cleaned off. Eely-Mouth has two separate pairs of eyes on either side of its mouth; one pair appears to be male, and the other female.

Eely-Mouth is aggressive and tries to swim upward and suck Mario into its mouth, after which it quickly spits him back out again. Large toxic purple bubbles regularly come out of its mouth, and will damage Mario if touched. If Mario sprays the bubbles with water from F.L.U.D.D., they will pop into a cluster of smaller regular bubbles that do not harm Mario, but rather replenish his air supply. Once all the teeth have been cleaned, Eely-Mouth retreats back into its cave, and spits out its golden tooth, which turns into a Shine Sprite that Mario must collect. As the eel recedes into its cave, it also leaves behind twenty Coins in a heart-shaped formation, which float just above the mouth of its cave (whether the player collects them or not is optional). After it has completely disappeared, F.L.U.D.D. comments "Remember to take proper care of your teeth!"

In Mario Golf: Toadstool Tour and Mario Golf: Advance Tour, Eely-Mouth's name appears on the scorecard, although it is highly unlikely that the eel itself actually plays golf.

The kind of species of eel that Eely-Mouth is is currently unknown.