She once open the ancient Chest of Triceratops and absorbed it's powers, meaning that she turned into a Were-Dino at every full moon. Her Were-Dino form was purple in colour due to her purple hair in Human form. (Attack of the Were-Dino).Polly seems to have a crush on Edgar after that episode.
In the 3rd episode of the first season, Edgar tried to impress Polly to save the day from his other friend's flower lil Edger. She is also a friend of the Posse.
Meet the Posse, Jurassic Roadshow, Flower Power, Straight Outta Megalopolis, Polly, I Shrunk the Dinos, Attack of the Were-Dino