Buttercup is "the tough one". Her signature color is light green, and she has short black hair in a flip. She was named because "Buttercup" begins with the letter "B" like her sisters, much to her chagrin. She is a tomboy and has a very short temper. Sometimes her aggression gets the better of her, making her reckless and stubborn. She possesses a mean and somewhat vindictive streak not shared by her sisters. She has, however, shown a softer side in several episodes. For example, in the episode "Cover Up", she had a soft green blanket that she was obsessed with that she would hug that gave her the confidence to be a better fighter, and she is quite protective over her sisters. She hates baths and loves getting dirty.

Interestingly, Buttercup is the only Powerpuff Girl without special powers (Blossom has her ice breath, and Bubbles can speak several languages). However, for not being special, she is the toughest. In "Nuthin' Special", it is revealed that Buttercup is the only Powerpuff Girl (and Townsville citizen) who can curl her tongue.

The Powerpuff Girls(c) Craig McCracken