Is it some sort of alien? A destruction-portending nightmare sent to bring our very civilization to an end?
No, its a cuttlefish. It kind of looks like that first though, doesn’t it?
I’ve seen these things three of four times while snorkeling around the Pacific Ocean, and I always sit and watch them for a while as one of the strangest looking creatures I’ve found underwater. In particular, their method of locomotion… that wavy little ring around the bottom… really kind of freak me out.