9. Mark Henry
There was a stretch in the mid 2000s when Undertaker had a lot of bad matches. It wasn't necessarily his fault. It was just that WWE kept putting him against bad opponents. There were some gems like at No Way Out 2006 against Kurt Angle (probably his best match not at a WrestleMania), but then that was followed up with this stinker at WresteMania 22 against Mark Henry in a Casket Match. Since WWE spent so much money on Henry for so many years they felt like they had to get something out of him, so they made him a serious heel challenger to The Undertaker. The result of that push was a boring, plodding battle at WrestleMania 22. At no point in the match did anybody really think that Undertaker would lose. Henry did some things where his power was impressive for a short period of time, but it wasn't a compelling match in any way. The only part of the match that was good was when Undertaker did a dive over the top that took out Henry. That led right into the Tombstone finish for the win in a 10 minute match that felt longer. They had other matches too. There was a rematch on Smackdown that led to debut of The Great Khali (more on that awful rivalry later) and even a Casket Match rematch two years after this. At least Henry did in improve in 2011, which was 15 years after his debut.