You were walking on the beach when you suddenly heard some humming from a deep beautiful voice coming out of a cave. You decided to explore further and walked into the direction of where the voice came from and found yourself in the cave where the only source of light comes from the hole in the top of the cave

Then you saw it, there was a man, or better halfman with a black fishtail instead of legs and long black hair sitting on a stone above the water and humming some melodies