Caeneus

Two Centaurs pound Caeneus into the ground with tree trunks; bronze relief from Olympia, Archaeological Museum of Olympia BE 11a (mid–late seventh century BC)[1]

In Greek mythology, Caeneus or Kaineus (Ancient Greek: Καινεύς, romanizedKaineús) was a Lapith hero, ruler of Thessaly, and the father of the Argonaut Coronus. Caeneus was born a girl, Caenis (Ancient Greek: Καινίς, romanizedKainís), the daughter of Elatus, but after Poseidon had sex with Caenis, she was transformed by Poseidon into an invulnerable man. Caeneus participated in the Centauromachy, where he met his demise at the hands of the Centaurs by being pounded into the ground while still alive.[2]