In keeping with tradition, The Undertaker was buried alive during Survivor Series 2003, before returning in 2004's Royal Rumble with a brand new look that many have dubbed as "Undertaker 2.0," as he'd have elements of the "American Badass" and the "Deadman" going forward. Recalling the process leading up to the aforementioned gimmick change, Mark Calaway claimed that he's retained elements of all his gimmick changes along the way.

"So, the Undertaker 2.0 there was –- even, I guess, it started with American Badass. I sort of started incorporating a lot of Jiu-Jitsu and stuff like that," he said, noting that he's always been an MMA and boxing fan. "UFC, they were growing so fast... So it just made sense."

Calaway explained that this specific gimmick change ended up allowing him to retain the dark sinister characteristics of the Undertaker while having a different style. "I was just able to continue to evolve it because wrestling fans can get real flavor of the week," the veteran pointed out. 

In hindsight, Calaway managed to keep his character relevant and only subtly changed the "Undertaker 2.0" gimmick over the years, before retiring as a new once-off variant of the "American Badass" and his "Big Evil" gimmick with supernatural elements, in the Boneyard match against AJ Styles at WWE WrestleMania 36.