Cynics may dismiss it as just a piece of driftwood or a trick of the light.
But a photograph showing what appears to be a long-necked sea creature has got marine experts scratching their heads.
The 'animal' was snapped stalking a shoal of fish just 30 yards off the British coast.
The fish were apparently so terrified they beached themselves just seconds later.
The creature was spotted off the Devon coast at Saltern Cove, Paignton, by locals who reported a sighting of what they thought was a turtle.
But pictures taken by one of the baffled witnesses, Gill Pearce, reveal the neck of the greenish-brown beast with the reptile-like head is far too long for it to be a turtle.
In the deep: The 'animal' was at first dismissed as a sea turtle but experts say its long neck and reptile-like head - as well as the fact it was chasing fish - contradict this theory