For all the Superman Cena memes, WWE's franchise player has been beaten clean at least half a dozen times. Shinsuke Nakamura did it on SmackDown last summer. Even Kevin Owens, a heel, pulled it off a couple of years ago at Elimination Chamber.
Cena losing, on its own, isn't what made SummerSlam 2014 so surprising. Rather, it was the manner of his defeat. He was basically thrown around the ring like a rag-doll, made to look like a nameless local jobber who's won a competition to appear on Raw.
The truly incredible part was that Brock Lesnar, his blood-thirsty opponent, could have ended the bout at pretty much any moment he wanted. He deliberately prolonged Big Match John's humiliation in order to add insult to a laundry list of injuries.
Why they decided to do this here - two years after the Beast Incarnate returned to the company - and not on his first match back at Extreme Rules 2012 (during the "worst year" of Cena's career") is anyone's guess, but we give two massive thumbs up for the shock value.