Magical Realist
Valued Senior Member
Looks like a blanket octopus.
I think it's a dead something-or-other. Internal organs (I think) show up around 4/5 of the way through; seems like an octopus that's had the mantle and head removed by something. That or the stalk-ish thing visible indicates it was sessile, whatever the hell it was. Fairly big though.
I'll go with blanket octopus that has met its maker.
The video was made in 2012. You would think the creature would have been identified, and it has. It's called Deepstaria reticulum and is a jellyfish.