Isabella Garcia-Shapiro (voiced by Alyson Stoner) is a Jewish Mexican American girl character from Phineas and Ferb. She is one of the brothers' best friends and has a crush on Phineas Flynn of which he is unaware, though he has shown he cares for her from time to time. Her first appearance is in the pilot episode. She is known for the catchphrase, "Whatcha doin'?" (which she doesn't like when other people besides Phineas say) and is the leader of the Fireside Girls troop 46231. The troop often helps Phineas and Ferb in their projects. She is named after series creator Dan Povenmire's oldest daughter.