Coastguard crews launched to a rescue found a stray Iron Man balloon floating in the water.
They’d received reports of someone in trouble at Kirkcaldy promenade in Fife on Thursday afternoon.
One witness thought they’d seen someone wearing a jet pack crash-land in the water.
However, when rescuers reached the scene, they discovered a blow-up version of the comic superhero.
A coastguard spokesman said: “We were called at 10.40am this morning after reports of a person wearing a jetpack was seen to enter the water at Kirkcaldy, Fife.
“The ‘person’ was seen to be hovering over the water and then disappeared.
“The HM Coastguard search and rescue helicopter from Prestwick was sent along with coastguard rescue teams from Leven and Kinghorn and the Kinghorn RNLI lifeboat.
“When the coastguard rescues teams arrived, they soon discovered that a large promotional inflatable Iron Man had been lost.
“The lifeboat had searched the water and no one was found so the helicopter was stood down.”
A spokesperson from Aberdeen Coastguard Operations Centre said: “The person who called us did exactly the right thing, we would always ask people to call 999 and ask for the Coastguard if they believe anyone is in trouble at sea or along the coast.
“Although this was a large promotional inflatable it does shows how easily inflatables can be swept out to sea.
“Please remember that blow up boats and toys are great fun in the swimming pool, but we do not recommend their use at the seaside.
“If people do find themselves being swept out to sea, our advice is to stay with the boat or toy and shout for help, waving arms if possible. Do not attempt to swim for shore if out of depth. Ideally make sure that someone ashore is keeping an eye on you.
“Also, If you lose any large object that potentially be confused as a person, vessel or an aircraft in the sea please contact the Coastguard.”