Sarah: Have you seen a capo anywhere?
David (sounding very much alarmed): What?!?!?!?!?!? A HIPPO????!!!!!!??????
Sarah: No - my capo.
David: You have a hippo?
A capo (short for capotasto, Italian for "head of fretboard") is a device used for shortening the strings, and hence raising the pitch, of a stringed instrument such as a guitar, mandolin or banjo. It was invented by the Flamenco guitarist Jose Patino Gonzalez. Capos are used to change the key and pitch of the open strings of a guitar without having to adjust the strings with the tuning keys. - Wikipedia