Penepole Steamtail is a Fright-Mare who inhabits the Dream Pastures, a secret place within the walls of the Monster High Catacombs, a place where the monster's dream collide. She was born when a butterfly had a dream that collided with a Nightmare from the Dream Pastures, creating the unique being, Penepole Steamtail.
Penelope has pink skin with blue eyes, long pink hair, and a horn on top of her head. Her body is half horse, centaur like, while her horse body is bright reddish-magenta like. Additionally, she has yellow butterfly wings.