Achelous

Achelous in Greek mythology, was the son of Oceanus and Terra. He wrestled with Hercules in contest for Deianira, daughter of king (Eneus, who was betrothed to both. He first turned himself into a serpent, then into a bull, when Hercules plucked off one of his horns and forced him to submit. Achelouis purchased his horn by giving in exchange the horn of Amalthea, daughter of Harmodius, which became the cornucopia, or horn of plenty, and which Hercules filled with a variety of fruits and consecrated to Jupiter. This fable is thus explained: Achelous is a river in Greece, whose course winds like a serpent, and its stream roars like the bellowing of a bull. This river divided itself into two channels, but Hercules, by confining the water of one, broke off one of the horns; the circumjacent lands, thus being drained, became fertile, so that Hercules is said to have received the horn of plenty.