The Fender Mustang is an electric guitar introduced in 1964. It was created as a redesign from the Fender Musicmaster and Duo-Sonic guitars. In the 1960's most of the "surf bands" used Mustang guitars, and in the 1990's Kurt Cobain led it's popularity once again, when Fender decided to reissue the guitar after much demand. On a side note, Cobain also originally suggested to Fender the combination of the Mustang and Jaguar guitar, which Fender later produced, called the Jagstang.
The original Mustangs are American made, most of the reissues are made in Japan. The early, 1960's Mustang editions hold the most worth, and are seen as the most collectible of all the short-scale Fender guitars.