A fabulous, serpent-like monster from Irish oral tradition. In one famous story, the Oilliphéist cuts the route of the River Shannon when it hears that Saint Patrick has come to drive out it and its kind.

The name is derived from the Irish oll, "great," and péist, "fabulous beast, monster, reptile." The Scottish Gaelic variant is called Uilepheist. See also Caoránach, Muirdris.

There is a comic addition to the story in which the monster swallows a drunken piper named Ó Ruairc (O'Rourke). The piper is either unaware of his predicament or is completely unperturbed and continues to play inside the monster's stomach. It becomes so annoyed with the music that it coughs him up and spits him out.



  • MacKillop, James. (2004). Dictionary of Celtic Mythology. New York: Oxford University Press, Inc.