For the most part, 'The Deadman's entrance at WrestleMania 22 wasn't all that different to his weekly entrances on SmackDown in 2006, but there were a few subtle changes that helped it to stand out.
A wall of fog descended from the larger stage, allowing him to look even more intimidating as he walked through it. Furthermore, the wall of flames served as the perfect backdrop, highlighting The Undertaker's awe-inspiring silhouette (this proved to be so effective that he would later incorporate it into his non-PPV entrances too). The cream of the crop, however, was seeing him stare at Mark Henry as he stood over that double-wide double-deep casket at ringside, essentially letting the 'World's Strongest Man' know what awaited him.
Sometimes, the little things make all the difference.