MULE, E.G. is a term used to describe an animal that is a hybrid of a horse and a donkey. The crossword solutions for this term are SHOE (4 letters), SLIPPER (7 letters), and BEASTOFBURDEN (13 letters). A SHOE is a type of footwear that covers the foot and provides protection and comfort. A SLIPPER is a type of soft SHOE that is usually worn indoors. A beast of burden is an animal, such as a mule, that is used to carry heavy loads.