Crash is the leader and lead singer of The Bettys. She is the Betty with the spiky, black hair and the Gothic look.
Like her band mates, she made Candace and Stacy do their chores on their tour bus. However, they apologized in the end. When the bridge in front of the bus is destroyed, Candace goes to the front to try and save it. Phineas and Ferb, who happen to be riding Perry's spy car, activate their magnet ray to save the bus, but the car doesn't have enough power. Then, Perry goes underneath and lifts the bus up with mechanical hands. The band, however, thinks that Candace saved them, and honor her by letting her sing on stage with them ("Ready for the Bettys").
She has a British accent, and sort of resembles John Lennon, since she is the lead singer.