Penguin

Penguins are characters in the Mario series.

Gameplay
The adult wants Mario to find Tuxie. Mario must carry Tuxie and return Tuxie to her.

In the DS version, if Yoshi eats Tuxie, Tuxie will say that she's not food.

Super Mario Galaxy
Penguins can be seen swimming in this game. They appeared in every game in the series of the Super Mario Galaxy series.

Mario Strikers Charged Football
The Penguins appear as audience members in the game.

Mario & Sonic at the Winter Olympics
Penguins only appear as audience members in Dream Curling.

Other media
Penguins only appeared in 7 Continents for 7 Koopas in The Adventures of Super Mario Bros. 3.