There's no escape!
The two play a similar role in the game as the movie. They taunted Ariel into thinking that Ursula will let her venture to other worlds if she traded the trident for her dream to come reality. Ursula sent Flotsam and Jetsam off to search Triton's palace for the Keyhole, but they were unable to find it. They later fought Sora and co. in Ursula's lair. After the fight, they curled up and die in a mist of ink.
In Kingdom Hearts II, Flotsam and Jetsam have returned probably the same way Ursula did. They only briefly appear in the song-battle 'Ursula's Revenge'. During the song, the two eels tried to suffocate Sora, but were destroyed when Donald and Goofy pull them off of Sora, allowing him to finally destroy them with a blast of magic from his Keyblade.
In the film, Ursula used Flotsam and Jetsam to manipulate Ariel into visiting Ursula. They used their sly and cunning ways to convince her into thinking she will live forever with her love, Prince Eric. They were both killed when one of Ursula's wayward shots of the King Triton's Trident hit the pair of eels.
Flotsam and Jetsam swim around Ursula's lair, attacking by biting periodically. Sora must focus on casting spells onto Ursula's cauldron. The main spells to use are Fire, Blizzard, and Thunder: the best of them is Fire, as it consumes little MP and it is the first on the Magic menu.
Flotsam and Jetsam revive periodically after being knocked out, so be sure to keep them at bay. Allow your party members, preferably Ariel and Goofy to take care of them while you focus on Ursula. Or, if you cannot, take them out yourself, and be sure that Ursula is far away from them when you knock them out—this will buy you time to bash Ursula left, right and proper when they are revived.
Stats & Abilities