10 WWE Superstars You Won't Believe Defeated The Undertaker
8. Mr. Kennedy (Survivor Series 2006)
The Undertaker's next feud in 2006 just so happened to be with Mr. Kennedy, who WWE was incredibly high on at the time and intended to push to the top of the card.
Kennedy was already in the midst of an impressive rookie year and was fresh off capturing the United States Championship one month earlier. The two didn't mesh well on paper, but their series of matches in the final few months of the year wound up being pretty good, including at No Mercy.
It was at that event Kennedy beat Undertaker by disqualification to retain his title before repeating the feat the following month at Survivor Series, this time in a First Blood match. Kennedy made the most of his push and was primed to go far, until he suffered several injuries that derailed his momentum and ultimately cost him his career in WWE.
Losing to Kennedy wasn't the worst thing for Undertaker, but considering it amounted to nothing, Kennedy's various wins over the multi-time WWE world champion were a waste. Of course, that was entirely WWE's fault. It wasn't going to get much better for him than that, so they shouldn't have waited so long to pull the trigger on his long-awaited main event run.
Oh, what could have been.