Police feared a woman had been murdered when a man handed in what he thought was breast implant.
But the squidgy circle proved to indicate something much less sinister.
A concerned man raised the alarm with cops in Queensland, Australia, last week after upon stumbling upon a translucent disk he believed to be a prosthetic implant .
He handed over the item to officers in the Sunshine Coast town of Maroochydore.
Police were initially said to be alarmed — but quickly established it was a jellyfish.
Senior constable Zoe Brady said: "Officers at Maroochydore station were all hands on deck when, much to their initial alarm, a concerned citizen attended the counter to report a possible homicide.
"The member of the public presented police with a bagged and tagged circular object he had located that day.
"Officers seized the item at the request of the man and provided him with a receipt.
"The man was concerned it was a prosthetic implant from someone who may have been murdered or drowned."
She added: "Investigations revealed what police suspected… the item was indeed a jellyfish."
The unfortunate creature is thought to have been a blubber jellyfish, which are common in Queensland's waters.
Its tentacles are likely to have been torn off by a wave or eaten by a fish, leaving it looking unusual — and, to some observers, the dead-ringer of a breast implant.