A seal was left with "horrendous" injuries after it got stuck in a Frisbee-style toy.
The plastic disc had been around the animal's neck for about six months, but no-one could get near enough to rescue it from Horsey Beach in north Norfolk.
Nicknamed "Mrs Frisbee", the toy began to choke and cut her as she grew.
Volunteers from Friends of Horsey Seals finally caught her on Thursday. She is being looked after by the RSPCA who said she could take months to recover.
The seal had evaded capture or help for some time.
Peter Ansell, chairman of the friends group, said: "It has been swimming around with the yellow Frisbee on its neck for anything up to six months,
"While it was still healthy and fit, it was in a bunch of seals - one would get spooked and they would all go - which made it hard to capture."
But recently, the group noticed the seal was deteriorating and looked "distressed". The rest of the seals had also left the injured mammal on its own.
The seal was captured and taken to the RSPCA's hospital at East Winch near King's Lynn.
Manager Alison Charles said: "She's a lot better than she was. She is alive and eating her fish.
"We managed to get the item off, but her neck is horrendous, I've never seen anything like it."
"It'll take months for it to heal."
The Friends of Horsey Seals said they had received other reports of a seal with a rubber tyre around its middle, and another with rope tangled around its neck and flipper.
They have warned against leaving litter on beaches and in the sea.