Esther Lin/MMAFighting

For all the Kimbo Slices and James Toneys of the UFC, there will always be Brock Lesnar: the circus experiment that went right.

In the world of professional wrestling, Lesnar was known as “The Next Big Thing,” a fairly elementary moniker that would one day prove true in the living, breathing sports world.

Initially, the hardcore MMA community thought it was a joke when the World Wrestling Entertainment superstar made the decision to turn in his ballet boots for a pair of four-ounce gloves. Pro wrestling is rehearsed brilliance that has the potential to go wrong night in and night out, but it’s nearly impossible to replicate the level of fear and anxiety an athlete faces before stepping into the cage against a trained fighter.

But Lesnar, a former NCAA Division I wrestling champion, stuck out his gargantuan chest and embraced the challenge. A common belief in combat sports is that fighters are born, not made.

What other way is there to explain the improbable run Lesnar would go on?

After three professional fights and a little more than a year's experience, he fought and defeated UFC Hall of Famer Randy Couture for the heavyweight title in November 2008. He went on to defend the title twice before succumbing to current UFC heavyweight champ Cain Velasquez at UFC 121 in October 2010 and former Strikeforce champ Alistair Overeem at UFC 141 in December 2011.

After incurring back-to-back losses and a serious medical condition, Lesnar closed the chapter on his four-year MMA career by announcing his retirement from fighting.

Despite the fact that he won the UFC title, one has to wonder what might have been if he had realized his full potential. What if he started his MMA career at a younger age? What if he was never diagnosed with diverticulitis, an intestinal disorder that led to his immediate exit from fighting?

Dwayne “The Rock” Johnson, an avid MMA fan and future WWE Hall of Famer, calls Lesnar’s MMA accomplishments “epic and historic.”

“I don't know if anybody will ever accomplish what he's accomplished in the heavyweight division in that short amount of time,” Johnson says on UFC Fight Pass' collection of Lesnar's fights, per Fox Sports. “Had it not been for the unfortunate issue he had to deal with his stomach, who knows what could have happened if he continued to train, and continued to hone in on his skills. What he did was epic and historic.”

Even today, it’s easy to reminisce about the good old days of a dim-lit arena and Metallica’s “Enter Sandman” cranked to the max, as Lesnar’s hulking figure stomped angrily down to the Octagon.

The mere thought of an individual winning the UFC title and becoming one of the biggest draws in the history of MMA in such a short period of time used to be preposterous. However, things were different for Lesnar, as fans accepted all of his absurdities and outlandish feats without batting an eyelash.

He went from being “The Next Big Thing” to the thing in MMA, and it only took him a year to do it.

Jordy McElroy is a featured columnist for Bleacher Report. He is also the MMA writer for Rocktagon.