¡Ay, caramba!

Ay, caramba! is a phrase commonly used by Bart Simpson. It is his second most commonly used catchphrase, behind Eat my shorts! "Ay caramba!" were also Bart Simpson's first words. He first said it when he was a baby and saw Homer and Marge in bed having sex. Bart uses this phrase to express surprise, emotional distress or discomfort.

Variations
Ay Ca-ram-ba! In the episode The Great Simpsina, after Lisa takes some scissors off Bart's mouth, Homer starts shaking him upside down, wich resulted in a paused version of the phrase.

Behind the Laughter

 * Ay, caramba! is Spanish for denoting surprise or pain.
 * Bart Simpson wasn't the only character to use this: A construction foreman who coincidentally sounded a lot like Bart Simpson also uttered it.
 * According to the comments for Teranoid's song Ay Carumba!!!! on the Teranoid Anthems: Live @ Underground album, the song title comes from Bart Simpson. Teranoid is a fan of the show.