A giant octopus by Pliny (not to be confused with the documented Giant Pacific octopus) Leviathan Cecaelias or Octopus people Sea monk Various sea serpents Tritons by Pliny Cormac Ua Liatháin in the 6th century supposedly saw a horde of tiny creatures the size of frogs that had spines, which attacked his boat in the North Atlantic according to an account written by Adomnan of Iona[4]