He's the notorious straw that stirs the UFC drink.

And though the jury remains out on whether Conor McGregor, circa 2020, resembles the competitive force that pushed mixed martial arts into the mainstream half a decade ago, he's no less a needle-mover.

The provocative Dubliner is back in the octagonal spotlight this weekend against Donald "Cowboy" Cerrone, who'll provide the initial litmus test as to whether there'll be a legitimate return to the A-side. 

If McGregor wins impressively, it'll be a Conor 2.0 world we're all living in.

The purists who cringe at his presence will have to respect the way he backs up incessant trash talk. Meanwhile, the perpetual contrarians will have him as a hero in case other flavors of the month turn sour.

And the folks in the middle? They'll at least have to concede the entertainment value.

"I'm going to put on a beautiful display on Jan. 18," McGregor told The Mac Life (h/t MMA Fighting). "Get my fans excited. Get the forgetful MMA industry, that's such a forgetful game. One guy can have a win or two wins and they're on top of the world, and a guy can have a loss and he's the bottom.

"I'm going to remind everyone and then continue to climb."

To prep for the return, we put together a collection of McGregor's greatest UFC moments since his arrival to the promotion seven years ago. Click through to see if your own lists jibe with ours.

7. TKO 1 Marcus Brimage

Remember April 2013?

Colin Kaepernick had just played in a Super Bowl. Adam Scott had just won The Masters. Connor McDavid had just turned 16.

And Conor McGregor was laying the foundation for a resume that could support his persona.

The chatty Irishman lobbed trash-talk grenades toward Marcus Brimage prior to making his UFC debut on a Fuel TV undercard from Stockholm, Sweden, prompting the American veteran to begin the match with an ill-advised charge across the Octagon.

Barely a minute later—67 seconds to be exact—the "Bama Beast" had been relegated to a semi-conscious speed bump, and McGregor had the makings of a notorious phenomenon.

6. UD 3 Max Holloway

Some moments get bigger as the years pass.

Case in point, McGregor's defeat of Max Holloway in August 2013.

The blessed Hawaiian was just 21 and still several fights away from attaining recognition as one of the best to fight under the UFC's featherweight banner. But he had just enough skill and mettle back then to push the Irishman through 15 grueling minutes on the way to dropping a competitive, but unanimous decision.

McGregor showed some mettle of his own in earning his 14th victory in 16 bouts, fighting roughly half of the 15 minutes with a torn ACL in his left knee—an injury that ultimately shelved him for 11 months.

5. TKO 2 Chad Mendes

Fast-forward two years and the McGregor star had risen considerably.

He'd picked up three more wins by July 2015 and finally landed the featherweight title shot he'd so cherished, set for the big stage in Las Vegas at UFC 189 against champion Jose Aldo.

Then Aldo got hurt and pulled out, leaving McGregor devastated but determined to stay in the show's headlining position. Chad Mendes was brought in as a replacement and made life nothing if not difficult in the early going, taking his foe down in the first round and leaving him bloody from an elbow to the right eye.

The American again put McGregor flat on his back in the second but lacked the stamina to finish the job. Ultimately, the Irishman regained his feet, began landing precision strikes—including a booming left hand with about 10 seconds left in the round—and prompted a rescue from referee Herb Dean with just three ticks left.

The win netted McGregor both an interim belt and a quantum leap in street cred as he pursued Aldo.

4. TKO by 10 Floyd Mayweather

Here's one worthy of debate.

Some will suggest—with perfectly valid reason—that McGregor's leap from the Octagon to boxing ring to face Floyd Mayweather was his ultimate achievement, regardless of the losing result.

We'll defer to actual victories, though, and keep it here.

Either way, though many have suggested such a crossover and a few have actually tried it on a smaller scale, none have captured the dual level of hardcore/mainstream attention as the ambitious McGregor warranted when he made the leap in 2017.

And none have been capable of the ostentatiously vulgar masterclass the mic-friendly combatants led from the start of their international media tour through the end of their register-ringing event.

A rematch has long been suggested possible, and with Mayweather once again teaming up with UFC czar Dana White, it seems as likely in 2020 as ever.

3. TKO 2 Eddie Alvarez

And now, we return to the winning side of the ledger.

By November 2016, McGregor had reascended the MMA mountain—more on that in subsequent slides—and was anxious to make UFC history by becoming the first man to hold two weight-class titles at the same time.

Standing in his way was a capable, rugged champion in lightweight Eddie Alvarez.

But compared to the dynamic McGregor, the Philadelphia battler was really little more than a sanctioning second banana as the Irishman topped the first MMA card at Madison Square Garden.

Alvarez was vaporized in just a shade more than eight minutes, making the winner a champion at both 145 and 155 pounds and providing the marketing fuel necessary for the aforementioned Mayweather circus.

2. MD 5 Nate Diaz

Into every combat sports supernova's life, a little adversity must come. And in McGregor's case, adversity was named Nate Diaz.

Hustled in as a late fill-in when the Irishman's scheduled opponent—then-lightweight champ Rafael dos Anjos—sustained a broken left foot, the Stockton gangsta derailed the McGregor Express with a shocking second-round rear-naked choke submission in their 170-pound get-together at UFC 196.

Needless to say, the unexpected result set up a UFC 202 rematch that was, in a word, lucrative. And boy, did it deliver—winding up as the most-bought pay-per-view (at the time) in the promotion's history.

The bout, named Bleacher Report's best of 2016, saw McGregor rally from another near-loss experience on the way to a majority decision.

In the words of CBSSports.com, in fact, he "arrived as a phenomenon" and "left as a fighter."

And, just days after a midweek press conference featured flying cans and bottles, McGregor touched gloves with his rival at the final horn and conceded, "That was the best fight I've ever had."

1. KO 1 Jose Aldo

He's won more championships. He's made more money. He's drawn more pay-per-view buys.

Without a UFC 194 erasure of Jose Aldo, though, it can be argued McGregor never hits those other highs.

The Brazilian entered the December 2015 fray without a loss in the previous 10 years and with widespread recognition as the best pound-for-pound fighter the promotion had to offer.

But in far less time than it took to order the event—a mere 13 seconds, in fact—the perpetually brash challenger landed a left hand that separated Aldo from his consciousness, his hardware and the unbeaten run he had been on.

He was all but comatose by the time he hit the floor, and the two further hammer-fists that viciously finished the job could have confirmed McGregor's superstar-level bookings on the Tonight Show, The Voice and Dancing with the Stars, all at the same time. 

"Nobody can take that left-hand shot," he said, via CBSSports.com. "He's powerful and he's fast, but precision beats power and timing beats speed. These are fundamentals. That's all it takes."