Mnemosyne — Classical Greek Myth Library

While Heracles is serving Omphale in Lydia (or, in some localizations, near Ephesus), he lies down to sleep and is set upon by the Cercopes—two brothers, trickster-dwarfs or monkey-like thieves, often named Passalus and Acmon (or Sillus and Triballus in variant lists). Their mother had warned them to beware a dangerous “black-bottomed” man (μελάμπυγος). They try to steal Heracles’ weapons; he wakes, catches them, and hangs them upside-down from a pole across his shoulders, their heads dangling toward his rear. As he walks they see his hairy black buttocks and laugh, realizing the omen; they banter so wittily that Heracles, amused, spares and releases them. In other tellings Zeus later turns the Cercopes to stone or into apes for their frauds. The adventure is comic relief in the Heraclean cycle: strength meets cunning and chooses laughter over slaughter. Catalogue it as a distinct side-myth of the Omphale year, not one of the twelve labors.