Clazmonian sow

The Clazmonian sow, which they called Phaea, was a savage and formidable wild beast, by no means an enemy to be despised. It was big and had wings. The Clazmonian Sow was one of the monsters whose mother was, literally, Echidna, mother of monsters. Others relate that Phaea was a woman, a robber full of cruelty and lust, that lived in Crommyon, and had the name of Sow given her from the foulness of her life and manners, and afterwards was killed by Theseus.

The Last Olympian
Percy had to face the Sow when Kronos and his army sent it in to weaken the demigods while his army killed them and tried capture Olympus. Percy stole a grappling hook and rope from Athena's cabin and swung it around the Sow's leg as it flew away. Blackjack the Pegasi came and let Percy ride on his back so that Percy could pursue the Sow. Percy attached the rope on the Sow's leg to a Hermes statue and then activated Plan Twenty-Three which made the Statue come to life and made it attack Sow. Percy then did the same thing with some Lion Statues. Then finally, with the statues help, Percy defeated the Sow, thus making him the first person to kill the Sow.