Wrestling is a dangerous business. As the famous saying goes: 'this isn't ballet'.
Sometimes accidents happen and WWE Superstars can get hurt.
There's also an unwritten 'rule' about what happens when your opponent gets 'stiff' and catches you for real.
You're entitled to give a 'receipt' - which, in simple terms - means you can hit them back.
It's not rare for things to go wrong inside the ring - as a young Randy Orton found out in 2005 when he accidentally caught The Undertaker with a chair and busted him open.
That's a story he recalled on an upcoming episode of 'WWE Untold: The Phenom and The Legend Killer' which will air this Sunday.
During the documentary, Orton brilliantly explains that he was 's***ting himself' about facing a 'receipt' from Undertaker and revealed what happened when it finally came.
"In my year-long programme with The Undertaker, I learned what a receipt was the hard way," The Viper begins.
"There’s a trajectory when you swing a chair. He’s on his knees, I back up and start to swing… But I was off.
"When that chair came down, I caught him with the lip of the chair, ripping the skin off his forehead down to the bridge of his nose and he was covered in blood.
"That wasn’t supposed to happen. So I’m s***ting my pants, we get to the back and I’m saying ‘sorry, sorry!’ He looks at me and says: 'don’t worry kid, your receipt is coming'.
"So I’m like oh s***. That sucks."
That accident happened on an episode of SmackDown in early 2005, but The Undertaker waited until their Hell in a Cell match at Armageddon in December to cash in his receipt.
Orton went on to explain exactly what happened that night.
"We’re both on the floor out of the ring. He grabs a chair, walks over and has the chair down by his side.
"I’m all f***ed up leaning against the apron. He looks at me and goes 'that receipt is coming now'.
"I look at him... 'okay, what the f*** am I supposed to do about that?'
"But even though he owed me one because I busted his a** open, he took care of me. Anyone else would have hit me as hard as he could.
"I learned an important lesson that day. Your number one priority is to take care of your opponent."
Even when Undertaker owed Orton a 'receipt' for catching him flush with a steel chair, he made sure to take care of his opponent inside the ring and never even considered actually hurting him.
That attitude is exactly what makes him a WWE legend.
WWE Untold: The Phenom and The Legend Killer airs on Sunday, October 25 on the WWE Network.
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