Some fans have long yearned for Brock Lesnar to be placed into a program in WWE with someone who at least appears to pose a legitimate threat to the former UFC heavyweight champion. Well, it doesn't get any more legitimate than the man who took the UFC heavyweight strap from Lesnar nine years ago. Friday night during the conclusion of the WWE SmackDown on Fox premiere episode, UFC heavyweight Cain Velasquez made his stunning WWE debut and immediately took aim at his former Octagon rival. 

Lesnar captured the WWE championship in mere seconds on Friday by dethroning Kofi Kingston. As Lesnar was celebrating his title victory, Rey Mysterio's music hit as some assumed he was coming for some semblance of revenge for Lesnar's attack that took place Monday night on Raw.

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Mysterio didn't come alone, however, as he was flanked by longtime friend Velasquez at the top of the ramp. Velasquez removed his shirt, hit the ring and began pummeling Lesnar on the mat until the new WWE champion retreated. Lesnar teased getting back into the ring for more of a scuffle, but in typical heel fashion, the "Beast Incarnate" wanted no part of it. 

Velasquez, 37, defeated Lesnar in dominant fashion at UFC 121 in October 2010 via first-round TKO to end the latter's heavyweight championship reign after just two successful title defenses. He last appeared in the Octagon earlier this year in February, a first-round TKO loss to rising heavyweight Francis Ngannou which also resulted in a severe knee injury. 

While he did debut Friday night on WWE TV, it was reported after SmackDown aired that Velasquez has not put pen to paper and signed with the company just yet. Velasquez is reportedly in "advanced talks" with WWE, though he has not officially retired from UFC, according to ESPN.

"This is definitely my focus," Velasquez told ESPN. "My family is into it, they love it. They're super excited. I haven't seen them excited over something like this in a while. It's cool."  

Velasquez has very much entertained the idea of a transition to pro wrestling throughout the course of the past year. Last summer, he took a trip to the WWE Performance Center where he spent time getting some training under his belt. This year, the longtime pro wrestling fan took the transition a step further, competing for Mexico's most prominent promotion, AAA, both during its annual TripleMania event as well as the company's foray into the United States inside the Hulu Theater at Madison Square Garden. 

According to a report form MMAjunkie's Mike Bohn, Velasquez intends to withdraw from the USADA testing pool. That move would end his time as a UFC fighter and signal a move to pro wrestling. However, Vasquez recently noted that he would only become a full-time wrestler following a necessary knee surgery.

It is unknown whether WWE is planning to run the Lesnar-Velasquez program immediately or perhaps hold it until WrestleMania 36 in Tampa, Florida. Depending on the severity of the knee surgery that Vasquez needs, pushing a potential match off could provide enough time for recovery while Lesnar feuds with Mysterio.

Reports have surfaced recently that there was a bit of a bidding war going on for Velasquez's services between WWE and upstart All Elite Wrestling, the latter of which appeared to be emerging as the favorite seeing as Velasquez teamed and trained with AEW superstar and executive vice president Cody Rhodes during his time with AAA. Ultimately, though, it seems WWE won out and we're on the road to one of the more intriguing feuds we've seen Lesnar involved in since his return to the company in April 2012.