Eely-Mouth is an eel only appearing in Super Mario Sunshine. He lives in the Nokis' ancestral home, a massive underwater chamber below Noki Bay, and his gingivitis was the cause of 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 his teeth is revealed to be golden once he is cleaned off. Eely-Mouth has two separate pairs of eyes on either side of his mouth; one pair appears to have a masculine appearance, and the other feminine.
At the start of the episode, the Noki elder will explain to Mario that he has finally figured out the problem as to why the bay is polluted, and will send him to the ocean floor to fight the giant eel. Due to his intense suffering, Eely-Mouth is aggressive and will spin around very fast, and then rise upward and open his mouth. This is when Mario can attempt to clean his teeth, by spraying them with F.L.U.D.D. After some time, Eely will suck in water, and Mario as well, if he is too close. If this happens, Mario is quickly spat back out and will lose air. Due to Eely's intense pain, toxic, purple tears regularly come out of his eyes. These tears will damage Mario if touched, but refill his breath meter. 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 replenish his air supply. Once all the teeth have been cleaned, Eely-Mouth retreats back into his cave, and spits out his golden tooth, which turns into a Shine Sprite which falls to the bottom, that Mario must collect. As the eel recedes into his cave, he also leaves behind twenty coins in a heart-shaped formation, which float just above the mouth of his cave (collecting them is optional), most likely as a sign of thanks. After Eely-Mouth has completely disappeared, F.L.U.D.D. comments, "Remember to take proper care of your teeth!"
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