Info On Toad

Fyi, Toad is not really a toad, but he's a cute and red mushroom head.
Toad – known in Japan as Kinopio (キノピ) – is a fictional, anthropomorphic mushroom in the Mario series, created by Shigeru Miyamoto. A citizen of the Mushroom Kingdom, Toad is one of Princess Peach's most loyal servants and is constantly working on her behalf. He is usually seen as a non-player character (NPC) who provides assistance to Mario and his friends in most games, but there are times when Toad takes center stage and appears as the main protagonist as seen in Super Mario Bros. 2 and Wario's Woods.
Toad's original role as a helper has been increasingly taken over by Toadsworth, causing Toad to appear less frequently than he once had in the main series; however, in New Super Mario Bros. Wii, two Toads (Yellow and Blue) appear as playable characters along with Mario and Luigi.Toad and the Toad species were first seen in the game Super Mario Bros. where the species was revealed to comprise the majority of the population of the Mushroom Kingdom. Toad's design was made directly from the power up, the Super Mushroom as well as the game's general association with mushrooms.[2] In the game, the peaceful Toads of the Mushroom Kingdom had been turned into various objects such as bricks and pipes by the evil King Bowser; however, some of Princess Toadstool's loyal servants, known as the "Mushroom Retainers" were simply kidnapped.
Two Toads (Yellow and Blue) were included as playable characters in New Super Mario Bros. Wii due to their physical similarity to Mario and Luigi.

Info from http://en.wikipedia.org/wiki/Toad_(Mario)