In "Be Stella My Heart", she is seen watching Lincoln, Clyde, Zach, Liam, and Rusty fight in the gym.
In "Racing Hearts", she is at the dance studio with her partner, Flat Tire, while participating in the Royal Woods Astonishing Quest.
She has poofy reddish and brownish hair, glasses, buck teeth, pale skin, and freckles around her face. She wears a pink sweater with a light green alien on it, dark teal skirt, lavender socks, and brown shoes.
According to Clyde, Penelope takes banjo lessons.
Even though she wears glasses, she has visible eyelashes. While most often, female characters who wear glasses have no eyelashes to speak of. She, along with Monica from "Cheater by the Dozen", are an exception.
The alien logo on her sweater is identical to the one on Tad's shirt.
She appears to be missing her canines, as when she smiles in "Shell Shock", there are holes where her canines would normally be.
According to "Out of the Picture", she is a member of the chess club, since she is seen in the group photo for the chess club.