Answer: Eel
In the Caucus Race scene, the Dodo Bird is on top of a boulder with a tiny fire to dry him off, and other sea creatures are running around the boulder to try to get dry. However, waves keep crashing on them and they get wet again. The water never touches the Dodo Bird, so he is the only one to actually get dry. Although they are very minor characters, you can see a pelican, starfish, and lobster running around the boulder. However, you never see an eel.