With its mysterious dark hump floating in the water, you’d be forgiven for thinking you’d just spotted the Loch Ness Monster.
And onlookers thought just that – after they were fooled into believing it was the legendary creature.
On closer inspection, experts say it is likely to be a basking shark lurking near the shoreline of the famous beach resort of Skegness.
The footage shows several fins bobbing up and down in the choppy water, just metres off the coast where children can be seen paddling in the shallow water.
People can be heard on the YouTube video shouting it is a basking shark.
But some observers likened the creature to the Loch Ness Monster because of a humped-back similar to the legendary Scottish beasts’.
Miss Clarke, who filmed what is believed to be a shark, thought at first glance it was rubbish floating on the surface but on further inspection realised it was alive.
She said: ‘It might seem silly but I thought it looked rather reptilian, like a crocodile or a dragon as the fins seemed more rigid than they do on sharks