Man Friday is one of the main characters in Daniel Defoe's novel 'Robinson Crusoe', published in 1719. After spending years marooned on a desert island with only a few animals for company, Crusoe spots a footprint in the sand which is not his own. This terrifies him, but no other man appears. He continues his solitary life and then some years later spots some cannibals using a remote beach on the island to eat their prisoners. One of the captives escapes; Crusoe helps him evade the pursuers, and then makes him his servant and calls him 'Friday' - since that is the day of the week upon which he finds him. It is not confirmed whether the footprint from years before belonged to Man Friday, but the reference here does show how ambiguous such an unexpected sight can be.