The worlds of pro wrestling and mixed martial arts exist in juxtaposition to one another. Indeed, both are superficially combat sports, with the big difference that MMA fights are legitimate, competitive sport, whereas pro wrestling is all about entertainment with predetermined outcomes and fabricated storylines.

Related: 10 MMA Stars Who Should Jump to Professional Wrestling

Athletes have crossed over between the two endeavors, and indeed there are fans who follow both forms, particularly as the lines have blurred with fighters like Conor McGregor all but explicitly tapping into the wrestling tradition with their trash talk and theatrics. Hostilities have arisen between wrestlers--WWE Superstars, in particular--and fighters on more than one occasion.

10 Chael Sonnen Vs. John Cena

Chael Sonnen John Cena

Chael Sonnen has earned the moniker “The Bad Guy” in part due to his trash talk game. That includes reaching across the lines from MMA to pro wrestling where he has taken aim at John Cena over social media. Cena is known to post abstract philosophical thoughts as a form of motivation to his followers. Sonnen, in turn, has taken to undermining Cena by pointing out where the thoughts don’t quite add up or making light of them. This comes years after Sonnen first broached the sixteen-time world champion, insulting him and publicly asking for a match as far back as 2011.

9 Becky Lynch Vs. Cris Cyborg

Cris Cyborg Becky Lynch

Before Becky Lynch exploded for the greatest run of her career that culminated in her main eventing WrestleMania and proceeding to reign as Raw Women’s Champion for over a year, she got into a Twitter beef with UFC’s Cris Cyborg. The exchange included Lynch telling Cyborg she’d be watching her fight, and Cyborg suggesting the two have a match at SummerSlam 2017.

Related: The 10 Worst Things Becky Lynch Did In Wrestling

Nothing came of it, but the exchange walked a line between fans of both women wondering if there was real heat between them, and others speculating they actually were working a wrestling angle.

8 Conor McGregor Vs. Sheamus

Conor McGregor Sheamus

There may be no wrestler to have more clearly pulled from the pro wrestling playbook of theatrics and cutting promos than Conor McGregor, whose sports entertainment antics paired with his fight game made him a megastar in UFC. He has engaged on social media with fellow Irishman Sheamus, with McGregor seemingly baiting the Celtic Warrior until he at last fired back. Sheamus ultimately walked the line between pro wrestling bravado and speaking pragmatically about size differentials in claiming he would absolutely “walk over” McGregor if they fought.

7 Roman Reigns Vs. Daniel Cormier

Roman Reigns Daniel Cormier

In the build to WrestleMania 37, Roman Reigns did media work in which he sold absolute confidence, including not only that he would smash his challengers, Daniel Bryan and Edge, but also that he could smash UFC champ Daniel Cormier. Cormier took to Twitter to fire back, saying that’s a fight he would take, and tagging Triple H and Vince McMahon to get their attention. Like a number of other wrestler-fighter clashes, some fans thought they smelled a work as if these two were setting up an angle.

6 Drew McIntyre Vs. Colby Covington

Drew McIntyre Colby Covington

In 2020, things got a bit heated between MMA fighter Colby Covington and Drew McIntyre during his underappreciated run as WWE Champion. Covington offered some big talk about how he might transition to sports entertainment and “make wrestling real again” in a visit to the What the Heck show. McIntyre didn’t like Covington making light of his work, and responded via ESPN that he’d shut up the much smaller Covington if he ever did fight him. Covington took matters to the next level in suggesting that once public health allowed it, he’d hunt down the Scots man and “take his soul out of his body.” Covington hasn’t made good on the threat to date, but the exchange got wrestling and fighting fans engaged for a minute.

5 CM Punk Vs. Cathal Pendred

Cathal Pendred CM Punk

CM Punk has walked both sides of the pro wrestling and MMA line, though he certainly has enjoyed much more success in the former than the latter. Before he stepped into the Octagon, he engaged in a Twitter war with Cathal Pendred. The fighter tried to call out now-AEW Champion, while Punk knocked Pendred for being boring and for calling out Punk as an easy target and because he had a much larger following.

4 Brock Lesnar Vs. The Undertaker

Undertaker Brock Lesnar UFC

Brock Lesnar and The Undertaker were, of course, noteworthy rivals within the confines of WWE, feuding during Lesnar’s original WWE tenure, then offering the spectacle of The Beast ending The Streak at WrestleMania 30, before a heated follow-up feud in 2015. Amidst all that action, it’s easy to forget their other feud that momentarily captured the imagination of fans, when they had a confrontation at UFC 121 in 2010. At that point, Lesnar was fully removed from pro wrestling, but The Undertaker attended one of his fights and the two had a brief, tense moment squaring off as The Beast walked by The Dead Man post-fight. The Phenom described in an interview with ESPN’s Ariel Helwani years later that he was trying to stir up intrigue and a potential WWE match, though it didn’t amount to much at the time.

3 Bryan Danielson Vs. Mike Jackson

Bryan Danielson Mike Jackson

In a Q&A with fans, Bryan Danielson commented that he could beat UFC fighter Mike Jackson “on the ground, for sure.” This was back in 2018, fresh off the heels of Jackson’s fight with CM Punk, and a Jackson cited this in warning Bryan not to let his “mouth write a check” he couldn’t cash. The two sparred a bit more on social media, but nothing more came of it.

2 Conor McGregor Vs. Chris Jericho

Conor McGregor Chris Jericho

Conor McGregor has had multiple run-ins with wrestling personalities. Chris Jericho, who infamously didn’t back down from a fight with Brock Lesnar, wasn’t about to shy away from conflict with McGregor over social media. That included Jericho suggesting McGregor’s fights were fixed.

Related: Conor McGregor Vs Dustin Poirier 2 (& 9 Other Times Losers Trash Talked In Defeat)

On another occasion, the two sparred over the semantics of being a “Champ-Champ” or double champion, with the Notorious one seemingly doubting Jericho’s claim to the title, and Jericho dismissing McGregor altogether.

1 Seth Rollins Vs. Colby Covington

Seth Rollins Colby Covington

Colby Covington’s pot-stirring at point one extended to Seth Rollins, whom he referred to in an interview with Submission Radio Australia as a “little cry baby.” Covington clarified he respected and was friends with a number of WWE talents like Ronda Rousey and Bobby Lashley who were legitimate fighters. It all smelled like a work—albeit one only Covington may have been in on—when he proposed a mixed tag match pitting him and Rousey against Rollins and Becky Lynch.