"We had about 40 people dressed up as their favourite superheroes to celebrate International Free Comic Day, so he didn't have much of a choice but to hand the X-Men Omnibus back after a little bit of a scuffle," he said.
"I've had a look at the security footage and it shows Spider-Man running down the corridor of the shop, grabbing this guy, hauling him off.
"Everyone in the store thought it was a play, that it was street theatre of some sort. It wasn't until I said `Call the police' that people started to realise."
Comic Centre and another bookstore encouraged patrons to dress as characters for the event.
"One of the funniest things about the incident was that I called for people to stand near the door and it just so happened we had people dressed as Jedi knights there blocking the exit, the Flash was there at some point too," Mr Baulderstone said.
Link -via Geeks Are Sexy