Witness The Undertaker make a surprise return to WWE on "Old School Raw."

Everything changed this past Monday on “Old School” Raw when The Undertaker’s gong rang through the halls of the First Niagara Center in Buffalo, N.Y., moments before The Phenom wordlessly declared his intention to compete at WrestleMania 29. By the end of the night he had a challenger in CM Punk, who outmaneuvered Randy Orton, Sheamus and Big Show in a Fatal 4-Way to claim the coveted spot of The Deadman’s opponent at The Show of Shows.

But while The Phenom returns from whence he came and Punk begins preparations for his biggest test yet, the WWE Universe — not to mention the locker room — is abuzz with excitement at the return of WWE’s most iconic Superstar. With The Demon of Death Valley headed back to The Showcase of the Immortals, the excitement is only building, and some of The Undertaker’s former rivals had plenty to say on both their battles with The Deadman and his forthcoming collision with CM Punk.

Sixteen-time World Champion Ric Flair, who was in town to accompany The Miz for his match against Dolph Ziggler, got particularly nostalgic over his own WrestleMania clash with The Deadman nearly a decade ago.

“It was awesome,” Flair said. “I never saw that opportunity coming because I had just come back in 2001. I didn’t plan on wrestling ever again and then I find myself WrestleMania with The Undertaker. It was a phenomenal experience.

“I think The Streak is great,” Flair continued on The Phenom’s spotless 20-0 mark at The Show of Shows. “No one deserves that position more than him and just the fact that I was able to be there at that point in time was fabulous for me.”

Big Show, who challenged The Deadman at WrestleMania XIX, warned of the high pressure that comes with a WrestleMania bout against The Undertaker. “When you see your name on a card next to The Undertaker and know you’re competing against him, your stress level automatically rises,” he said. “It pushes you to a level that you don’t push yourself to with other talent.”

The World’s Largest Athlete went on to describe The Streak itself as “monumental” and offered a ringing endorsement of The Phenom to WWE.com. “I’ll say it on record, I don’t care what anyone says. I think he’s the best ever in the ring, period.”

“The Million Dollar Man” Ted DiBiase, who was instrumental in bringing The Undertaker to WWE in the first place, voiced similar opinions to Flair’s and the giant’s.

“Obviously it was one of the bigger rivalries [I.R.S. and I] had, Undertaker being who he is and the entity he’s become in WWE,” DiBiase told WWE.com. “It was a chore; he’s already dead … how do you beat him? It was very hard.”

Irwin R. Schyster joined in on his old friend’s comments, labeling The Undertaker as an “unstoppable force.” But the famous taxman still harbored one specific beef with The Phenom. “Being a dead man, he doesn’t have to pay taxes,” I.R.S. said, “which was a very sore note for me.”

DiBiase, as always, brought it right back around to the bottom line when the subject of WrestleMania came up. “I can already see those great big dollar signs,” he cackled.

Mick Foley also weighed in on the subject. The three-time WWE Champion never faced The Phenom at WrestleMania, but still stands one of Undertaker’s most iconic foes, most memorably at their epic 1998 Hell in a Cell clash at King of the Ring.

“Everyone seems to get it,” The Hardcore Legend said of the locker room sentiment surrounding The Deadman’s return. “It’s the perfect guy doing the perfect thing with the perfect music and he makes the situations he’s in perfect as well ... The guy is timeless. He is The Undertaker.”

And with The Phenom’s 21st WrestleMania match fast approaching, WWE.com sought one final opinion on the bout with a Superstar who knows The Undertaker perhaps better than anyone: his brother Kane.

“The unique thing about The Undertaker, and probably the thing that is most underrated, is that he has the ability to adapt that a lot of people don’t have,” the WWE Tag Team Champion said. “The fact that he can change is why he’s been so successful and has been able to endure so long.”

And as for that looming WrestleMania bout, Kane — who fell to his brother at WrestleMania XIV and XX — had a few words of prophecy for WWE.com.

“CM Punk’s got his work cut out for him for sure,” he said. “There is no one better at WrestleMania than Undertaker and there is no one that will be more on top of his game at WrestleMania than Undertaker.”