Know someone who's obsessed with Halloween, lives for horror movies and reckons they're pretty much un-scarable?

Well, even they probably wouldn't make it through the world's most extreme haunted house. There's a $20,000 cheque on offer to anyone who can finish a tour of McKamey Manor in Tennessee but so far no-one ever has. Entrants have to pass a doctor's medical exam and a drug test, sign a 40-page waiver, have health insurance and undergo a background check before they can go inside. They also have to agree on a safe word. If they do head in, they face an ordeal up to ten hours long. Clips online show participants being blindfolded, submerged in water tanks filled with eels, screamed at, buried in mud, having a drill put in their mouths and even having hair shaved off during the tour. Owner Russ McKamey says he has poured over $1 million into the attraction – but concerns have been raised about him and the house. One previous visitor said she was waterboarded and whipped at McKamey Manor while another said she feared she was going to die. McKamey has downplayed the accusations of cruelty, saying visitors have exaggerated their claims. “It’s psychological what we’re doing. They’re safe all the time," he told Nashville Scene. Still, the stories haven't put people off. There are 24,000 people on a waiting list to get into this house of horrors, reports TooFab.