Bullet looks like any other squirrel in Townsville, being born to a normal family of squirrels. Bullet looks exactly like her siblings that are briefly shown at the beginning of the show, with brown fur and large orange eyes, though Bullet's eyes are meant to look like the other Powerpuff Girls.
In the episode "Stray Bullet," the girls briefly added another fourth member, a squirrel whom Bubbles had given Chemical X, whom they named "Bullet." The Powerpuff Girls first meet Bullet when Bubbles rescued Bullet from a hawk and takes the squirrel home. During the night, Bubbles feeds the squirrel drops of Chemical X in hopes that help the squirrel heal faster, which soon leads to Bullet developing powers similar to the Powerpuff Girls'. The girls officially adopt Bullet as a Powerpuff. However, Bullet feels that she must protect her animal friends and decides to go back to the woods.
Bullet still resides in the forests outside Townsville, where she protects the animal community, but she returns to help the Powerpuff Girls from time to time. The only other time Bullet appears in the series, however, is in "The City of Nutsville." When Bubbles gets stung in the throat by a bee and is unable to speak, she calls on Bullet to help her when angry squirrels swarm the city and she is unable to communicate with them. They eventually figure out that the squirrels were trying to retrieve their acorns, which were buried underneath the Mayor's newly-planted statue. Bubbles and Bullet destroy the statue, and some time later, a new statue of the duo is placed in honor of all the squirrels in Townsville.
Supersquirrel strength, similar to the Powerpuff Girls.
Supersquirrel speed, similar to the Powerpuff Girls.
Supersquirrel durability, virtually immune to physical harm.
Regenerative healing Factor, as she healed from catastrophic injuries at a rapid pace.
Supersquirrel stamina, does not tire for a long time of exertion.
Supersquirrel sense of hearing, can hear danger several miles away.
Supersquirrel sense of smell, can smell & track beings.
Ability to chew through plates of solid steel
Understanding of animal languages
Extremely stretchable cheek pouches (which have the capacity to contain a human)
Bullet can also "fire" nuts from her mouth by stacking up large quantities and exhale them quickly
Apart from the three Powerpuff Girls being Metahumans, Bullet on the other hand is a Meta-Animal, (also known as a Superpowered Animal, or just a Superanimal). These kinds of animals are much more stronger than regular ones, being able to defeat threats that animals couldn't defeat on their own.
Being considerably lot smaller than the Powerpuff Girls, therefore having much less mass, Bullet is able to move a lot faster than the Powerpuff Girls, being gifted with the same power. This statement is supported by the girls having a hard time catching up with Bullet at times.
In the episode "Stray Bullet" Bullet is constantly referred to as a girl. However, in the episode "The City of Nutsville" Bullet is referred to as a boy. This has lead to total confusion about Bullet's actual gender.
However, Blossom have in the past also referred to Twiggy as a male even though others called her female. This could indicate that Bullet is female.
In The City of Nutsville, Bullets home in the woods appeared to be a forest version of Townsville, complete with a mayor (who was a beaver), and a Powerpuff hotline (a blinking firefly).
Like the PPG, Bullet has two other siblings (unknown genders) and also appears to have a single parent.
Bullet has a "B" in their name and a double letter (Bullet) like the Powerpuff Girls.
Bullet does Blossom's signature pose at the end of "Stray Bullet" as the narrator declares that she has saved the day once.