|~ Vanessa's catchphrase|
Vanessa "Nessa" Doofenshmirtz (born June 15) is Dr. Heinz Doofenshmirtz's daughter who always knows what her father is up to some evil schemes to wreak havoc in the Tri-State area.
She was voiced by Olivia Olson, who also voices as Marceline Abadeer from Adventure Time.
Vanessa's behavior is comparable to that of a typical teenager. She cares about her reputation, having been upset when her clothes were mistakenly switched with Candace's. Vanessa has always been found with the "punk" or "goth" crowd, as seen in her childhood photos and her friends' appearance ("Hail Doofania!", "Dude, We're Getting the Band Back Together", "Brain Drain").
It is evident that she desires to have a car of her own. She once tried to prove herself responsible enough to own a car by trying to acquire a rare element, Pizzazium Infinionite, in the Superduper Mega Superstore for her father when he needed it ("Vanessassary Roughness"). She has also shown this when he told her he'd brought her a gift which would be in his words, 'The key to her happiness', openly hoping for a car, but dismayed to find out it was a Mary McGuffin doll she had asked for when she was seven. ("Finding Mary McGuffin")
She is or was on her school's swimming team. She also performed ballet as a young girl and was in a school production. ("Finding Mary McGuffin")
Although she tries to deny it when around her father, she is evil to a small extent. She has aided in Heinz's schemes on rare occasions, zapping pigeons with a hypnotic device as part of his plan to have them release their fecal waste upon the mayor on one ("Tree to Get Ready") and picking up blueprints for his "Space laser-inator" he would use to control Danville on another ("I Scream, You Scream"). She'd even snatched a Mary McGuffin doll from a little girl when she felt the need to keep her father's gift to her ("Finding Mary McGuffin"). The most prominent display of this trait was during the Summer Solstice while she was in Paris when she "rented" a scooter, threatened Major Monogram with a hairdryer acting as if it was a weapon, and hijacked Agent P's hovercar to make her escape ("Phineas and Ferb Summer Belongs to You!"). Though largely in denial of the evil inherited from her father, she has admitted her possession of it.
Vanessa has blue eyes, dark brown hair, which she wears long and freely down her back. She wears a tight-fitting black leather coat, black long pants, and black calf-high boots. She is also a beautiful and slender teenager. She did not inherit any of her father's features except the color of her hair and the color of the eyes. Her clothes are in the basic military Goth fashion. She wears black goth clothes and when a mix-up at a laundrette leaves her in Candace's clothes, Vanessa thinks she looks like a candy cane.