It was an 18 year old with a learning disability and mental age of 13. The central heating pipes in his parents house would knock due to air in the system. You have to question why his parents thought it was suitable for him to watch if he was that impressionable and unable to separate fact from fiction, despite there being many, many clues that suggested it was staged.

It scared the crap out of me, but I was 9 years old. Deep down I understood it wasn't real though.