#4 The Undertaker

At Summerslam 2015, The Undertaker aimed to make Brock tap-out, but only because he had tapped first.
In a shockingly controversial twist, The Undertaker did indeed tap to the Beast's Kimura Lock, though was saved from losing to Lesnar once again, as referee Charles Robinson didn't see it.
Shockingly though, this wasn't the Deadman's first tap-out, as the Phenom of the WWE would do the same during a match with Kurt Angle in September 2003.
Meeting on SmackDown, the pair had an epic encounter, with Angle making the Deadman tap, but at the same time that Angle's shoulders were pinned to the mat.
Even today, fans speculate about whether the Deadman's submission loss should count, but regardless, it still is one of the most shocking sites in the history of the WWE.