3 Times winners were changed mid-match in WWE and 2 times they were changed beforehand

#2 Brock Lesnar vs. Roman Reigns for the WWE World Heavyweight title (winner was changed before the match)

Seth Rollins' Heist of the Century is a landmark moment

Heading into WrestleMania 31, Brock Lesnar was the WWE World Heavyweight Champion, while Roman Reigns was determined to dethrone The Beast and win the top prize at The Show of Shows. The original plan was to have Reigns beat Lesnar and win the big one, but it was changed during the event itself. After Seth Rollins lost to Randy Orton, he was informed that he would be cashing in his Money in the Bank contract during the main event, thus making it a Triple Threat match.

Rollins came out during the main event, as the arena erupted in unison over what was happening. In a matter of seconds, Rollins pinned Reigns and won the WWE World Heavyweight title in possibly the most unexpected ending to a WrestleMania ever.

Fans had been booing Roman Reigns for a long time at that point, especially after his Royal Rumble win. WWE must have sensed that a Reigns win would lead to disaster, and decided to change the finish of the match at the last moment.