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. Of course, the word "Grandma" could merely be a term of endearment used by Peach, not describing an actual blood relationship.