Hoot the Owl
From the Super Mario Wiki
“You should lay off the Pasta, Mario!”
Hoot the Owl is an owl who sleeps in a tree near Whomp's Fortress in Super Mario 64 and Super Mario 64 DS. When Mario climbs into his tree, Hoot will offer to give Mario a ride to the top of the fortress. When Mario hangs on to Hoot too long, Hoot complains that Mario's weight is making it difficult for him to carry him for so long. He drops Mario, and tells him "to lay off the pasta." Depending on where in the sky Mario is, Hoot's action of letting him go could result in Mario's death.
He later appears at Cool Cool Mountain, Snowman's Land, Tall Tall Mountain, and the tiny (where everything else is huge) part of Tiny-Huge Island in the DS remake. He also appears as an unlucky gambler in Mario Party Advance. Hoot tells the player that he has a losing streak at the Jungle Game Hut, and he needs the player to help him. Once the player wins, the reward is the minigame. The ending states that he can't stop shaking his head. In Super Mario 64 DS, music plays while hanging on to him. The music that plays is a remix of the Wing Cap theme.
Hoot is very similar to the Heavy Zeds from Super Mario Land 2: 6 Golden Coins and the generically-named owls of Wario Land II and 3 in that all these characters are sleeping owls who will help the game's protagonist when awoken, and finally background owls in Super Mario 64 and Super Mario 64 DS, which only make sounds.