Orthos
This dog guarded the desirable red-purple cattle of Geryoneus that were stabled in hidden barns on Mount Abas in Greek myth. It gave tongue when Hercules came to steal the cattle in his tenth labour and was assisted by the centaur Eurytion, but even the hero clubbed the dog to death.
John and Caitlin Matthews, The Element Encyclopaedia of Magical Creatures, 2013, Orthos p 356
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