9. The Undertaker KOs The Referee At The Start Of The Match Versus Shawn Michaels - In Your House: Ground Zero, September 1997
The entire arc of this feud escalating from being built around a chairshot to having to be solved in the Hell in a Cell structure is masterful. However, it wasn't the chairshots take either Taker or Shawn took in the feud that strikes me as the scariest moment overall. Actually, from a psychology standpoint, it's the referee getting "recklessly" bumped before the match even begins at In Your House: Ground Zero that pretty much sets the tenor for just how "outside of the box" this feud would eventually become. From a pure psychological standpoint, if a seven foot tall tattooed undead man is willing to unmercifully smack around someone completely unrelated to anything regarding the issue you have with him because he's in the way, that's a great reason to be completely scared of his intentions towards you. It also nicely set the tone for the level of fear and insanity there was to come.