4. The Resurrected Deadman (1994 - 1996)
The Undertaker's SummerSlam 1994 return is one of the most iconic moments in WWE history, and it kicked off a new chapter for him. But his attire wasn't the only thing different about him, as the original Deadman persona allowed him to humanize his character a bit more over the course of its two-year run.
Originally just an extension of the Western Mortician gimmick (except with purple), he stalked and preyed on his opponents with ease. However, he soon began to loosen those shackles a little bit, allowing himself to take more damage from his opponents and do more exciting stuff in the ring. His rivalry with Mankind not only produced some of his finest in-ring work, it showed off that 'Taker could be taken down (temporarily) by the right opponent - and that was far more interesting.
Technically, that might make The Deadman gimmick a bit weaker than its predecessor, but it showcased the strength of Mark Calaway as a storyteller and performer, and allowed him to do far more interesting things in the ring. So, yes, from a kayfabe standpoint, it might be a little weaker, but in real life, it was the beginning of a far stronger time period for The Demon From Death Valley.
The evolution of The Undertaker would continue (and continue to amaze at the same time).