Dorrie is a sea dragon that swims around in the lake in the bottom of Hazy Maze Cave. He can be groundpounded to lower his neck, which lets Mario get onto his head, giving him a higher spot to jump from to either the star platform or the entrance to the Cavern of the Metal Cap. Whilst on Dorrie, Mario can control him by facing in the direction he wants Dorrie to turn, or to face forvard if Dorrie needs to go forwards.
A sign near the elevator leading to the lake reads the following: “A gentle sea dragon lives here. Pound on his back to make him lower his head. Don't become his lunch.” This text is misleading though, because Dorrie does not have a hurtbox. (citation is STROOP)
Later versions of Dorrie
Dorrie's appearence in Super Mario 64 is only his first, as he later makes appearences in Super Mario 64 DS, New Super Mario Bros, Mario Party 2; 3; 4; 5 and advanced, Dr. Mario World and with his latest appearence in Super Mario Odyssey.