The Crommyonian Sow (also called Phaea or Phaia Φαια after the woman who owned it) is a mythical pig in Greek mythology.
Crommyonian Sow Wikipedia
The Crommyonian Sow was a wild pig that ravaged the region around the village of Crommyon between Megara and Corinth, and was eventually slain by Theseus in his early adventures. According to Apollodorus, it was said by some to be the daughter of Echidna and Typhon, and was named after the old woman who raised it. According to Strabo, the sow was said to be the mother of the Calydonian Boar. Hyginus says that the pig that Thesesus killed at Crommyon was a boar.
Plutarch repeats the story, but states that he had also been told that Phaea herself was a murderous female robber, and was nicknamed "Sow" because of her uncouth manners, and that she was the "sow" killed by Theseus.