A couple others:
This one isn't clear enough to see if it's jellyfish-shaped, but it's close enough, and weird.
Some people on Twitter are pointing out the similarity to the Petrozavodsk phenomenon, which reminds me of this bit from that recent session:
I was thinking that maybe these jellyfish sightings and I had a thought about craft being analogous to our cells.
Maybe there are two categories for the ontology of craft - by accident, and by design?
In the case of a designed craft, a portion of 4D is folded in 4D by the engineers, creating it's own 'cell wall' or 'cell membrane' that allows it to interface with 3D. Meanwhile, the frequency within the wall or membrane is still 4D, and as such the 3D rules of space-time don't apply, which allows for small ships to have huge interiors.
Sort of like this - blue is 4D, pink is 3D. The purple dots are 4D guys. The resulting vesicle is a UFO.
The designed ships might also somehow fold themselves, just like our cells do! They're a sort of intelligent ship that's been a plot feature of sci-fi and fantasy novels. I'm picturing 4D ship-farmers who sort of 'seed' ships and tend to them as they grow up in a ship nursery or something like that.
In the case of a sighting of something purely accidental, seems that some portion of 4D gets enclosed, 'split off' and enters into 3D somehow. Maybe it's a craft that was in the process of growing itself (?), or maybe some 4D amateurs made a mistake, or sometimes just some weird chunks pop out of 4D into 3D from time to time. Anyways, due to this being incomplete or accidental, it wouldn't be as tightly bounded and properly shaped like the designed craft, possibly not having as much internal cohesion, and maybe limited 'intelligence' or directional ability if it is indeed alive in some way.
It would be similar to the diagram above, but the thing's gold 'membrane' might be misshapen (and possibly jellyfish-like, instead of disc, tic-tac, or triangular, etc?) and maybe there's no conscious purple guys inside, just the blue '4D interior' that is leaking out into the pink 3D space.
Anyways, the thought of the ships being alive or conscious in some way is pretty fascinating. I wonder if in 4D one can imbue matter with intent, 'enlivening' it in some way...