The Desert mouse, also known as Muad'Dib, is an adapted kangaroo mouse found on and adapted to the planet Arrakis. It is associated in Fremen earth-spirit mythology with a design visible on the planet's second moon, and is admired by Fremen for its ability to survive in the open desert. The desert mouse's native Fremen name was chosen by Paul Atreides upon his acceptance into Sietch Tabr.