Peggy Sue (a.k.a Peggie Sue) is a green humanoid alien pedestrian in Planet 51. She appears at the beginning of the race missions when a player is ready to race. She is also an unlockable multiplayer character, she can be unlocked if the "Looking for Rover" mission is complete. She can only be playable in multiplayer mode. In the movie of Planet 51, she is one of the background characters. The look of her is similar to the game version of Planet 51.
She appeared in the Planet 51 movie and video game on the wii and ds versions of the game, and on Escape from Planet Earth.
- "Looking for Base 9" is the only race mission Peggy didn't appear in
- In "Voorde's Challenge", she says "Ready...Set...Go!" after Voorde takes off.
- Her voice is similar to Peach's voice based on The Super Mario Bros. Show.