Maybe a sea dragon or a prehistoric sea dwelling dinosaur, that didn't die with the rest of them, ocean hydra,or maybe it's more like the loch Ness monster and maybe the music and people attracted it or maybe the yacht party was a sacrifice of some kind by someone on the yacht and only 20 to 25 percent of the ocean has been explored so far because of how deep the ocean water and how bad the pressure is down in the darkest depths of like Marianna's trench and who knows what ancient sea creatures call a place like that home?