The Undertaker made his WWE retirement official at Survivor Series. 

After 30 incredible years, he's finally walking away from the ring and fans are really going to miss him. 

Across three decades, The Phenom has had some storied rivalries - and one even transcended the wrestling world and spilt over into the UFC.

We're talking of course, about his clash with Brock Lesnar back at UFC 121 in 2010. 

That night, the pair came face-to-face outside the Octagon after The Beast had suffered a first-round TKO defeat to Cain Velasquez.

For years, fans were desperate to know if the confrontation was planned, or if there was real animosity between the pair following Lesnar's departure from WWE six years prior.

The incident was discussed during The Undertaker's recent appearance on Broken Skull Sessions, which aired last Sunday. 

Getting straight to the point, Stone Cold Steve Austin asked Mark Calaway - the man behind WWE's iconic character - why he was cage-side and if he was 'shooting an angle'. 

"Business brother," Undertaker simply replied.

"Forward-thinking, I was there to pick a fight. [Brock] knew I was there, but my whole mindset there was strictly to pick a fight and start a buzz. 

Undertaker was there to create a buzz for Lesnar's WWE return

"I knew it wouldn't take much and that was nothing. That was really, I mean it was so simple but it created such a buzz. It's just a shame it took so long for it to come to fruition."

Austin then asked about Brock's mindset after his loss to Velasquez that night and if that affected The Undertaker's decision to confront his rival. 

"What most people don't realise is he went out of his way to come by me. Obviously, I'm thinking in my head 'you just got stopped in the first round, maybe I shouldn't do this'. 

Undertaker and Lesnar faced off cageside at UFC 121

"But Brock came that way. So I'm like I'm gonna shoot. I'm gonna go with it. Whatever happens, happens. That was my mentality." 

The Undertaker then went on to suggest that he had 'vaguely covered' creating that angle with Lesnar beforehand, appearing to confirm once and for all that it wasn't a full 'shoot'. 

Still, it's fascinating to know the thought process behind it, especially when it comes directly from the WWE icon!