On man has reportedly experienced something heavily feared by many - he woke up during a surgical procedure.
Fen Settle, 25, was undergoing an operation for a ruptured appendix when he claims to have regained consciousness while still in surgery. He explained feeling a "stabbing pain" in his abdomen and feeling like he was struggling to breath because on a tube in his throat.
"I went down for surgery and everything was fine, I was put under but came round and felt like I had a bottle cap in my throat," he told Metro News.
"I thought I was going to die and tried to hold my breath so I would pass out quicker. I then realised I could hear voices, the beep of the machines and a stabbing pressure on my abdomen.
"I was able to figure out what was going on and that I was still in the operation. I couldn't move, I was paralysed. I tried to open my eyes, scream, wiggle my fingers and toes."
Hoping to alert the doctors that he was awake, Mr Settle "made the conscious decision to urinate". He says he was put back under and woke again after the surgery.
Doctors told him his horrifying experience was "all a dream".
Since the incident, Calderdale and Huddersfield NHS Foundation Trust in the United Kingdom has apologised and received compensation in an out of court settlement.
Fenn however, has returned to work but still suffered from post-traumatic stress and flashbacks after the ordeal.