Dolphin
The dolphins wear water goggles and Jump out of the water in Super Mario World. They only appear in Vanilla Secret 3 and can be used as platforms to cross the water infested with Porcu-Puffers. In the Japanese version, Yoshi can eat them. In other versions, they can't be harmed or affected in any way.
A dolphin appears in Mario Party 4 where he will let the character get on his back while the dolphin swims through the water. The character can Jump to get Coins.
Super Mario Sunshine had an island called Isle Delfino. The island was shaped like a dolphin too.
A comedian Dolphin is met in Mario Party Advance, one of the players quests involves helping him get his confidence back by listening to his jokes and laughing at them. Also several Dolphins will appear and form an audience to listen to his jokes.
In Mario Party 7, some Dolphins can be seen jumping out of the water in the file select screen.
Dolphins somwhat resemble Dorries.
