“[Amphitryon, the step-father of Herakeles] undertook a campaign against the Teleboans, inviting Kreon [king of Thebes] to join him. Kreon agreed to do so, if first Amphitryon would free the Kadmeian Land [Thebes] of its Fox. For a wild Fox was creating havoc in the land. But despite Amphitryon’s attempts, it was fated that no one would subdue this Fox. As the land continued in torment, the Thebans once a month would set out one of the citizen’s children for it, for otherwise it would have seized many of them. Amphitryon went to Deioneus’ son Kephalos at Athens, and after promising him a share of the booty from the Teleboan expedition, persuaded him to bring to the fox- hunt the Dog [Laelaps] which Prokris had received from Minos and brought from Krete, for it was also fated that this Dog would catch whatever it chased. Consequently, when the Fox was chased by the Dog, Zeus turned them both to stone [the only solution to the contradictory fates of a Fox destined never be caught being chased by a dog destined to catch whatever it chased].”

Pseudo-Apollodorus, Bibliotheca 2. 57 (Aldrich translation)