Walkers found the unusual statue on the island’s Compton Beach early on Sunday morning.
Tom Dunford, 29, saw the 10ft reflective monolith while he was out on a walk with his fiancee and sister.
Mr Dunford told Sky News: "We went down the steps and to the right about 100 yards in front of us we saw this big reflection of the sun.
"I knew about all the monolith stories recently, so I recognised it straight away,” he said, adding that it was clearly the work of someone playing “a practical joke”.
Monoliths have been the subject of international headlines in recent weeks, after the first was found in the desert in Utah on 18 November, before disappearing nine days later. Others followed on a mountain in California and a hill in northern Romania.
All of these objects resemble a giant monolith encountered by monkeys in Stanley Kubrick’s classic film 2001: A Space Odyssey.
While no one knows for certain who is responsible for the monoliths, the Most Famous Artist collective in Sante Fe, New Mexico, has claimed credit for the two statues found in the US and is selling three replicas for $45,000 (£34,000) apiece.
This comes after Bret Hutchings, a helicopter pilot who first spotted the Utah monolith, told local news station KSLTV about his theory of the statue’s origin.
“I’m assuming it’s some new wave artist or something or, you know, somebody that was a big 2001: A Space Odyssey fan,” he said.
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