It's like something, well... straight out of a Harry Potter film.

A plaque mysteriously appeared overnight outside Bristol's children hospital 18 months ago.

The sign claims the giant coloured rings outside the hospital are in fact the 1998 Quidditch World Cup goal posts, dedicated to the children of Bristol.

Thousands of "muggles" see the plaque every week but in all that time, the hospital had no idea it was even there.

So was it the work of a wizard with a marauders' map and invisibility cloak? Or possibly down to a revealing charm?

Nobody knew, until now.

It's been revealed the plaque was the idea of Bristol University graduate Cormac Seachoy, who died of cancer last year.

The 27-year-old used crowdfunding to pay for it, before sneaking out at midnight in November 2014 to glue it onto the wall.

He tweeted a picture the next day, but very few people seemed to notice.

The Lollypop Be-Bop sculpture is actually an interactive art installation with coloured lights that can be turned on and off by children inside the hospital, by remote control.

But Cormac's accomplice, and friend, James Carberry told Newsbeat: "He always used to say how the sculpture looked like the Quidditch posts.

He wanted the children at the hospital to think they were a gift from wizards James Carberry

"He wanted the children at the hospital to think they were a gift from wizards."

"We met outside the hospital and he came with this beautiful bronze plaque and a tube of industrial strength adhesive," he says.

The only problem was, they didn't have anything to open the tube with.

"He sent me to a pub around to ask for scissors, pretending we were opening a pop-up shop around the corner.

"I'll never forget the look on the barman's face as I asked him for the scissors, but he reluctantly agreed and we were able to put the plaque up."

The plaque claims the rings were enchanted by Adou Sosseh, the captain of Senegal's Quidditch team which lost the 1998 World Cup to Malawi.

That's something only diehard Potter fans would know. It was only ever revealed on JK Rowling's Pottermore website.

The hospital has now said it will keep the plaque but asks that other "magical beings" who want to put up plaques ask permission first so "muggles" at the hospital can thank them and maintain them.

It says: "The appearance of this plaque was a magical and mysterious event that we did not know anything about, but we are sure that our patients and their families will appreciate it".

James says Cormac, who was passionate about fundraising and helping good causes, would be thrilled.

"It would really put a smile on his face to think that people are now talking about the plaque and that the hospital's decided to keep it.

"He didn't really want much attention from the plaque.

"He just wanted to do something that would make people smile on their way in and out of the hospital."

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