According to greekmythology.com (I'll keep their hyperlinks so you can refer to their webpage for further research.) Arion was an immortal horse in Greek mythology, which was very fast and bred by the gods. According to a source, it also had the ability to speak.
According to Thoughtco.com, Antaeus was the son of Gaia and Poseidon. He was a Libyan giant whose strength appeared to be invincible. Antaeus challenged all passers-by to a wrestling match which he invariably won. Upon winning, he always slaughtered his adversaries. That is until he met Hercules.