Frog

Frogs are a species of animals that first appeared in Super Mario World 2: Yoshi's Island, however named Frog Pirates in that game.

In the Mushroom World, there is a pond inhabited by large, anthropomorphic, sapient Frogs in the duration of Super Mario RPG: Legend of the Seven Stars,  Mallow was raised by the Frogs, specifically Frogfucius and believed that he, himself, was a Froggy as well. The young tadpoles comprise a greater part of the population than the Frogs, of which there are only two.

Frogs also appeared as enemies in Yoshi's Story during Stage 4-4: Neuron Jungle. They swarm any Yoshi crossing the lagoon. Although any Yoshi could eat them, Green Yoshi liked them best.

In Mario Party 6, some Frogs can be seen in the background of Towering Treetop.

Wart from Super Mario Bros. 2, is a frog.

In Super Mario Bros. 3, there is a Frog Suit that allows Mario to become Frog Mario. Luigi can also become Frog Luigi.