Gramma Toadstool

Grandma Toadstool is the grandmother of Princess Peach Toadstool. She appears in Super Mario RPG: Legend of the Seven Stars. During the game, Grandma Toadstool dresses up as the princess so Peach can sneak out of the castle and join Mario on his adventure to defeat Smithy and recover the seven Star Pieces.

Grandma Toadstool is a Toad, meaning that Peach is not fully human. In fact, this means that Princess Peach is at least one-fourth Toad, unless, of course, that Grandma Toadstool had been disguising herself as a Toad (she showed great ease in disgusing herself as the Princess).