Crab Boss? Siren PVE suggestion

I think I've heard that there's talk at Rare of a giant crab PVE encounter on islands and I think that would be awesome. My idea is the chance for sirens to swarm your ship out at sea and crawl up the sides. You have to shoot them off before they sing or reach a point in their song, or they'll lure you off the ship and drown you. Maybe they can tear away at your ship slowly too. A sort of mirage island of the sirens that spawns at random inside the shroud seems interesting too. If you get too close and someone is steering, it can subtly turn your wheel in it's direction.