This was photographed by a friend on the roof of a neighbouring caravan at his holiday site on the north-east coast of Scotland last week.
I assume it must have been dropped by an over-flying gull. He didn't retrieve it and says it was about 2 inches in diameter (the "body" bit) with "lots" of tentacles about 5 inches long.
He's curious to know what it is - or rather was - and I'm afraid I don't have the foggiest idea! At a wild guess some sort of cuttlefish?
This is, as far as I am aware, the only photo.
Thanks for looking!