UK TV host and wildlife biologist Lizzie Daly and her crew were diving off the southwestern coast of England as part of their Wild Ocean Week initiative when they met this magnificent and massive barrel jellyfish. Typically, barrel jellyfish aren't bigger than meter long but this one was closer to 1.5 meters. From The Guardian:
Daly and an underwater camera operator, Dan Abbott… stayed with the abnormally large, translucent bell-mushroom-shaped animal for about an hour before it swam away.
The pair said they were not surprised by the animal's behaviour. "It has got a very mild sting and poses no threat to humans – some people don't even feel it," Daly said. "Many people would be immediately worried, but it is not dangerous. Its a majestic creature."