Guillard is perhaps the most confounding fighter in mixed martial arts. He's a powerful striker, he's got a great chin (his KO loss to Donald Cerrone at UFC 150 notwithstanding) and he's as dynamic athletically as anyone in the sport.
It's confounding, though, to see a guy win five in a row and inching ever so close to a title shot to all of a sudden lose three out of four and be stopped in the first round in all of those.
But if you're a fight fan, here's a piece of advice: Don't try to figure out Melvin Guillard. Just enjoy him.
Guillard is perhaps Exhibit A in the Dana White model of favouring performance over results. The UFC president has repeatedly said he prefers fighters who, you know, actually fight rather than those who play it safe and try to score a points win.
The lightweight contender, who meets Jamie Varner on Saturday at the Hard Rock in what he vows will be the best match of "The Ultimate Fighter 16 Finale," may occasionally shock but will never bore.
Whether he's on the winning end or the losing end, jaws usually drop during a Guillard fight.
"I don't go out there to play around," Guillard said. "I go out there to fight."
He's been repeatedly accused of recklessness and of not being able to maintain his emotions in order to win when it matters most. He had won five in a row heading into UFC 136 in Houston last year, where he was favoured to beat Joe Lauzon.
Lauzon, though, beat Guillard in less than a minute, hitting him with a counter left and then submitting him.
That loss, coupled with subsequent defeats to Jim Miller and Cerrone have left him far from the title picture.
Perhaps, though, it's not fair to Guillard to judge him in a traditional manner. And despite 44 fights, Guillard is still only 29 and still growing as a fighter.
He doesn't want to be distracted at this point from doing what is important to him – putting on a show that will bring the fans out of their seats – so he brushes aside any and all talk about the title.
He doesn't, he says, have a plan on how to get back into contention. He's not concerned about anything beyond an electrifying battle with Varner.
"You know, this fight should be the main event," he said. "It's the real main event in my opinion. We are going to go at it, believe me."
Varner, a former World Extreme Cagefighting lightweight champion who rejuvenated his career with an upset win over Edson Barboza at UFC 146 in May, similarly expects fireworks.
Guillard has been finished 10 times – nine by submission and once by knockout, by Cerrone at UFC 150 – while Varner has never been knocked out.
He told The MMA Corner there are plenty of similarities between Guillard and himself.
"I would say I'm a little bit more durable than Melvin," Varner said. "I've never been dropped. I've never been knocked out. Not to say that it can't happen, [because] Melvin is one of those guys that's been known to knock people out that have never been knocked out. He's hurt people that have never been hurt before. I'm a little bit more battle-tested.
"I can go into the later rounds and still fight. Even if I'm tired, I have that mental toughness that I can still grind it out. We have some of the same abilities. We both have raw power in our hands and our feet. But my wrestling and grappling is better."
There is plenty of time for Guillard to improve on those aspects of his game. He turns 30 in March, so he still has several years of what should be his prime left.
He may still harness that potential and become the smart, consistent and entertaining fighter everyone expects him to be. He may yet become a regular winner and move up the ladder of the world's best lightweights toward a title shot.
If it doesn't happen, though, not too many people are complaining about the current version of Guillard. Win or lose, he'll put on a show every time.