Leticia Gomes Santiago and her boyfriend Devanir Souza were taking a walk on the beach in Ilha Comprida, Sao Paulo state, Brazil, on 20 November when they made an unusual discovery - a spooky skeletal hand.
"We think it is not human because of the size and amount of bones. What could it possibly be?" Leticia wondered, suggesting that the discovery could be part of an alien.
The couple filmed the hand with long boney fingers next to Leticia's flip-flop to illustrate the size of the find.
The images have been analyzed by marine biologist Eric Comin, who said the hand probably belonged to a cetacean - aquatic mammals whose members include whales and dolphins - and judging by the decomposition, the animal died about 18 months ago.
His deductions were made at first glance, noting that more testing would be needed to pinpoint exactly which sea creature the mysterious discovery belonged to - although he is convinced it was probably a dolphin.