Woudn't suprise me if it was real.
It's belived there are some unseen races of fish etc. in the deepest spots of earth, where no submarines can go yet (mostly cause of the huge pressure down there).
Only few carcases have been found, which drifted to the beach.
for example that new octopus which was found like 1 year ago.. was 15+ meters long.. saw a picture of it.. it was a fucking huge. scientists say that octopus was one of the _smallest_ of its species.
Who knows, maybe we have a lochness monster down there lol
I think there was one jellyfish nicknamed 'battleship' or something, which is the largest. I'm guessing on the exact measurement but I think the largest can grow up to 2 meters in diameter.
The first pic is 100% fake.
Like Seko said, there might be larger jellyfish at the bottom of the ocean but we haven't found it yet. The deeper they live, the bigger they get so it wouldn't be crazy if larger jellyfish existed.