1990 was an interesting year for pro wrestling, especially the WWF. We were still a few years away from the steroid trial that nearly toppled the company - a trial that Vince McMahon seems to have had won simply through sheer tyranny of will - but the huge explosion of popularity the company saw in the 1980s was slowly starting to die down. WrestleMania VI - Hulk Hogan vs The Ultimate Warrior - took place that year, which was more than enough to hold on to the public's imagination. But things were clearly starting to slow down.
At the time, the World Wrestling Federation was very heavily gimmick-based - nearly every wrestler had a "job." There were wrestling police officers, plumbers, sanitation workers, and more. The Undertaker was just that - a mortician, and apparently one with supernatural powers, at that. His new manager, Paul Bearer - played by one William "Percy Pringle" Moody (himself a former mortician) - solidified the Dead Man's persona even further.
A year later, Undertaker defeated Hulk Hogan for the WWF Championship (with a little help from Ric Flair) - both cementing his legacy and giving me nightmares for months. The ultimate evil wrestler had defeated the beloved WWF champion (and my favorite wrestler at the time - remember, I wasn't even 13 yet.)
But, as evil as The Undertaker was... the man playing him did such an amazing job that, even as a little kid, you couldn't help but respect the guy. Even find him cool. Because he was cool. And, eventually, WWE pulled the trigger and made The Undertaker a force for good.
Which is weird when you look at it objectively but was still awesome.