In "Painting the Town..." she tells Ruby that she is actually a robot, saying that, "most girls are born but I was made."
Penny has short, rather curly orange hair that comes down to her chin, and she wears a pink bow on the back of her head. She also has bright green eyes, light skin and freckles. She wears an old-fashioned blouse with short feminine overalls, as well as a black and green collar with a matching pair of stockings.
The green lines on the side of her stockings also appear to glow at times. She has what appears to be a small and thin backpack, though it has only been seen when she came to the aid of Ruby Rose in "Black and White." Otherwise, she is not seen to have this backpack; only her normal clothing is shown.
Penny speaks robotically, behaves erratically, and is overly active in general. All her actions and emotional states are rather extreme and overacted. When Ruby unintentionally made an unconditional offer of friendship, Penny seemed both immensely pleased and somewhat surprised. Another small quirk is that Penny hiccups whenever she tells a lie.
She also seems to place great value on friendship, as she was greatly angered at the sight of Ruby getting knocked down by Roman's flare in "Black and White." She also placed trust in Ruby based on the latter promising that she is her friend in "A Minor Hiccup."
Furthermore, Penny seems to be immensely curious. Upon hearing that Blake had run away, she asked Ruby numerous questions, all being related to Blake and friendship in general. Despite being told not to wander off, she still wanders Vale on her own.
Upon confiding in Ruby that she was a synthetic being, Penny was worried about how she would take the news. However, after seeing how Ruby took it rather well, she was glad that Ruby didn't care if she was a machine, for what mattered was her heart and soul.
In "Dance Dance Infiltration," she is shown to enjoy dancing, as she is seen dancing by herself between two Atlas Soldiers. Later that night, she's seen doing "the robot" with one of the soldiers.