Post-fight at UFC 121 Ariel Helwani of Fanhouse MMA interviewed WWE's The Undertaker otherwise known as Mark Calloway, and the interview was odd to say the least.

A longtime fan of mixed martial arts the WWE veteran has been seen at numerous events before and is a known friend of his former colleague Brock Lesnar.

However Calloway seemed lost for words and really struggled to speak about Lesnar's performance at UFC 121 and how he felt the fight went down.

Then as Lesnar left the arena the two had a brief stare down and comments were exchanged regarding whether or not they were "going to do this."

Now what could this mean?

As an occasional follower of WWE I know that Calloway is nearing retirement and it has been widely reported that the next WrestleMania in April 2011 will be his last show. For wrestlers, who you fight in your last fight is a big deal, and Lesnar's name has repeatedly been mentioned as a possible opponent for Calloway.

The two had great feuds when Lesnar was in the business and there is no doubt his return if it were to happen even as a one-off would be a huge deal.

There are more questions than answers at the moment surrounding this topic but one thing is clear: There is some major tension between these two friends.

I'm guessing that Calloway wants Lesnar to return as a favor to him but Lesnar doesn't want to do it.

Let's hear your thoughts on this.