Any marine biologists here?

My browsings around the web in search of miscellany eventually brought me to this video: and I’m wondering what the heck the critter depicted is (the aquatic one, that is), assuming it actually is one, and not just some construction made to confuse the TV audience. It looks kind of like a hula skirt siphonophore, but its (forgive the lack of technical terminology) upper component is much narrower and shaped differently. I searched briefly, but every even remotely similar video I found was the same footage, which makes me suspicious.

So I come to you good people. Any idea what this is?

Siphonophores are weird critters. They’re sort of a colonial organization of jellyfish- and anemone-like “zooids”, each with different specializations. Some will be specialized for propulsion, others for feeding, and others for reproduction, and they’ll all look very different.

I am not a marine biologist, and I can’t identify that particular critter. But its body plan is consistent with what I do know: it’s got small bell-shaped propulsive zooids on top, and tentacled zooids on bottom. Here’s a good reference on the basics of the siphonophore body plan.

ETA: There’s an example of a similar looking siphonophore here, named Physophora hydrostatica. It appears to be much smaller, but it has similar looking zooids with similar arrangement.

I’m a marine biologist (more of a biological oceanographer actually, but that’s a distinction 99.9% of people don’t really care about). Most of the organisms I studied were just lines on a gel to me, and I’m certainly not an expert on siphonophores (or cnidarians in general, for that matter), but the organism in the video is almost certainly a siphonophore, at least to my eyes. As you probably know they’re incredibly diverse morphologically speaking, and are one of the go-to groups when people are looking for examples of “crazy-looking shit that lives in the ocean.”

Just to cram in another question: could Thor Heyerdahl and company have seen something like that in the open ocean aboard the Kon-tiki? They described it as luminescent, motile enough to dive, change direction and circle the raft. This was at night and the thing stayed submerged. It was as big as an elephant.