I've heard some stories about Bad News Barrett which make him sound like the toughest motherfucker alive.
Okay found a post on /r/squaredcircle that covers this whole topic.
First off: Haku. This story from Rick Steiner really paints a picture;
"I was in LA one time with him and he fought eight cops, they shot him with mace and he closed his eyes and sucked it in. He just opened his mouth and took a deep breath. I mean, some of the stuff he did was like "What the hell" Scotty and I always thought we were tough guys but that was before we met Meng."
People were legit scared of him, such as Jake the Snake;
If I had a gun, and I was sitting in a tank, and I had one shell left, and Haku was three hundred yards away, he's mine, right? Well, the first thing I'm going to do is jump out of the tank and shoot myself - because I don't want to wound that son of a bitch and piss him off.
Also about Wade Barrett. He fought in underground fight clubs throughout Europe. Here's a little excerpt from his experience of being stabbed:
"Unfortunately, I hadnt planned my getaway well enough. As I walked through an alleyway in search of a taxi to the airport, I heard footsteps behind me and a split-second later, I was jumped from behind and stabbed in the back with an eight-inch blade. I remember feeling the initial pain of the wound, but it was very quickly masked by numbness as the pain endorphins kicked in. At this point, I was supposed to stay down on the ground in agony whilst my assailant made off with my winners money, but things didnt quite work out like that. I lost a lot of blood that day, but I wasnt about to lose a penny of my hard-earned cash. I cant say too much about what happened next due to legal reasons, but what I will say is that if Ive ended up with 12 inch scars on my body, just imagine how the other guy ended up looking. If you cant imagine it, just go and look at some minced beef next time you are in the supermarket and that should do the trick. Life for me has always been full of scars and scrapes, but I make sure that I leave any situation with the money in my pocket."