Mule

From Tardis Wiki, the free Doctor Who reference
Mule
Giovanni leads an art-laden mule. (COMIC: Treasure Trail)

A mule was a pack animal. The Fourth Doctor once used many mules to transport priceless Italian art. When Nazis working for Hermann Goering attempted to remove the art via rail near Borosini, Italy in 1944, the Doctor blew up the line. He used the mules to retrieve the art and carry it down the mountain to the safety of the TARDIS. (COMIC: Treasure Trail)