#3. Fighting The Deadman
Rey Mysterio is perhaps one of WWE's safest wrestlers and he became good friends with the likes of The Undertaker and Randy Orton pretty early in his career. Despite this, Mysterio has had a number of slip-ups in the ring where he has miscalculated just how heavy he can be when he's flying through the air, and actually caused an injury.
Back in 2010, Mysterio and Undertaker faced off on SmackDown Live and The Master of the 619 was able to land a senton in the face of The Deadman, which left him with a broken nose and a concussion.
Undertaker was able to win the match, but he was left bloodied and bruised following his battle with Mysterio which would have left him less than impressed since Mysterio is less than half his weight and size.