Triton (Τρίτων, gen: Τρίτωνος) is a mythological Greek god, the messenger of the deep. He is the son of Poseidon, god of the sea, and Amphitrite, goddess of the sea. He is usually represented as a merman, having the upper body of a human and the tail of a fish.

Like his father, he carried a trident. However, Triton's special attribute was a twisted conch shell, on which he blew like a trumpet to calm or raise the waves. Its sound was so terrible, that when loudly blown, it put the giants to flight, who imagined it to be the roar of a mighty wild beast.

(from: en.wikipedia.org)