Source: William Smith, Dictionary of Greek and Roman Biography and Mythology
He lived at Potniae, despised the power of Aphrodite, and did not allow his mares to breed, that they might be the stronger for the horse race. According to others, he fed them with human flesh, for the purpose of making them spirited and warlike. . This excited the anger of Aphrodite or the gods in general, who punished him in this way:—when Acastus celebrated the funeral games of his father, Pelias, at lolcus, Glaucus took part in them with a chariot and four horses but the animals were frightened and upset the chariot.
According to others, they tore Glaucus to pieces, having drunk from the water of a sacred well in Boeotia, in consequence of which they were seized with madness; others, again, describe this madness as the consequence of their having eaten a herb called hippomanes.
It was believed on the Corinthian isthmus that it was haunted by the shade of Glaucus, who frightened the horses during the race, and was therefore called rapdynnros. (Paus. vi. 20. § 9.)
Glaucus of Potniae was the title of one of Aeschylus' lost tragedies: the whole family of Glaucus was exterminated before the third generation. The same story is alluded to by Pausanias (ii. 18, 2, viii. 7. § 4), and by Juvenal (xiii. 199).
Then that clammy fluid, rightly named hippomanes in shepherds'
language, oozes from their groin: the hippomanes that wicked
stepmothers often gather, and mingle with herbs and baleful
From The Georgics of Virgil, Book the Third