Rivalries and mixed martial arts go hand-in-hand because of the nature of the sport. In the past, fighters have regularly talked trash about their opponents during interviews and press conferences.But in the age of social media, everybody seems to be on Twitter. Some of your favorite UFC fighters are active on the popular online platform. And because of that, rivalries have spilled over into the digital realm, with fighters using Twitter as a platform to call another fighter out or just diss their arch-rivals.On that note, let's take a look at five instances when Twitter exchanges between UFC fighters turn ugly.#5 Conor McGregor vs Dustin PoirierUFC 257: Poirier v McGregorThe hottest Twitter feud currently is Dustin Poirier's accusation of Conor McGregor's empty promises. It started when Conor McGregor posted a photo on Instagram, captioned with a prediction for their upcoming third fight at UFC 264.Poirier replied on Twitter by accusing McGregor of flaking on his promise to donate $500,000 to his charitable foundation.That's a fun prediction! @TheNotoriousMMA you also predicted a donation to my foundation and you and your team stopped responding after the fight in January. See you soon. July 10th Paid In Full!— The Diamond (@DustinPoirier) April 11, 2021McGregor responded by claiming he never received a breakdown of what Poirier's charity would do with the money. According to McGregor, he doesn't simply make donations without knowing where the money is "going dot for dot."A donation, not a debt. We’ve been awaiting the plans for the money that never came. I do with all my donations. Know where it’s going dot for dot. Otherwise it goes walking. As is the case with a lot of these foundations, sadly. You took the McG over the belt shows I was right.— Conor McGregor (@TheNotoriousMMA) April 12, 2021Right now, it appears that the trilogy bout between McGregor and Poirier is in jeopardy after the Irishman tweeted a series of profanity-laced insults towards Poirier, before calling the fight off.You’re ripped you inbred hillbilly. Why do you wink with your ears? You fucking brain dead hillbilly. 500k with no plan in place. Ye hang tight. Fool. You must be new to money. The fight is off btw. I’m going to fight someone else on the 10th. Good luck on your old contract kid.— Conor McGregor (@TheNotoriousMMA) April 12, 2021The UFC has yet to release an update regarding the scheduled main event bout between McGregor and Poirier on July 10.#4 Aljamain Sterling vs Petr YanUFC 259 Blachowicz v Adesanya: Weigh-InsBad blood between Aljamain Sterling and Petr Yan started brewing when the latter lost his UFC bantamweight title in their UFC 259 fight via disqualification.Petr Yan and Aljamain Sterling were seemingly on good terms when the former champion posted an apology shortly after their controversial championship fight.I apologize and wish speedy recovery to @funkmasterMMA I didn’t mean to throw an illegal strike, I just made a big mistake and paid for it.— Petr “No Mercy” Yan (@PetrYanUFC) March 7, 2021However, Merab Dvalishvili – Aljamain Sterling's Russian-speaking teammate – informed 'Funk Master' that Yan was calling him a clown on his Instagram stories. At that point, Sterling quickly retaliated with a tweet..@PetrYanUFC please allow me to cleanly knee you in the temple, while you aren’t looking! See how much of a “clown”I would be then.I can admit RD 4 you were starting to land more shots, but the fight was statistically close, despite me fatiguing early.The clown here is you. https://t.co/gL2kWAupii— Aljamain Sterling (@funkmasterMMA) March 7, 2021Right now, both men take every opportunity to diss each other on social media. On Twitter, Yas posted several GIFs of himself getting the upper hand on Sterling and memes making fun of the new champ. The Russian has also accused Sterling of overselling the damage he took from the illegal knee.Unfortunately, a championship rematch between Petr Yan and Aljamain Sterling will not happen anytime soon. It was recently revealed that Sterling will be going under neck surgery that could keep him out of action for several months.#3 Jorge Masvidal vs Ben AskrenUFC 239 Masvidal v AskrenThe rivalry between Jorge Masvidal and Ben Askren is well-documented. It started with a lot of of trash talk from Ben Askren and ended with a perfectly-timed flying knee from Masvidal – a moment that shall live forever through GIFs and knockout highlight videos.One year ago today, Jorge Masvidal knocked out Ben Askren in five seconds at UFC 239#UFC #UFC251 pic.twitter.com/0OFdp29oA1— Jon Realejo (@BloodyCanvasJon) July 6, 2020This rivalry, however, is not yet over as far as Jorge Masvidal and Ben Askren are concerned. The bitter enemies still hurl insults at one another from time to time. The most recent episode of their on-going Twitter feud came when Masvidal called Askren a "crotch sniffer" ahead of the latter's upcoming boxing match against YouTube star Jake Paul.The individual I buried does not represent MMA. He represents all the hard core and casual crotch sniffers #andnew— Jorge Masvidal UFC (@GamebredFighter) March 28, 2021Of course, Ben Askren didn't back down as he responded by referring to Jorge Masvidal's famous flying knee highlight as a "lucky" KO win. He also claimed that he was the only reason why Masvidal is popular.I’ve refrained for 2 years, but let’s be real Jorge. You landed the luckiest knee of your life and I made you famous. You’re welcome. You got 50-43’d by Usman and will likely again next month. Beat it loser. https://t.co/JwZyaxGYa1— Funky (@Benaskren) March 29, 2021Soon, Ben Askren will be making his pro boxing debut against Jake Paul. And no matter what the result of that fight turns out to be, it's safe to assume that we'll be hearing from Masvidal and Askren on Twitter once again.#2 Jon Jones vs Dana WhiteUFC 200 New York Press EventWhen Francis Ngannou defeated Stipe Miocic for the UFC heavyweight title at UFC 260, Jon Jones immediately expressed his desire to challenge 'The Predator'. Jones, however, made it perfectly clear that he will only do so at a price that he deems fair to his value.Show me the money— BONY (@JonnyBones) March 28, 2021Instead of negotiating with Jon Jones, however, UFC President Dana White chose to insult the former longtime light heavyweight champ by accusing him of being terrified of Ngannou.“If I am Jon Jones and I am home watching this fight, I start moving to [1]85 [middleweight division]," White said in the post-fight press conference of UFC 260.White's comments set Jones off, who went on to launch multiple tweets about his qualms with the UFC brass. In a now-deleted series of tweets, Jones dared the promotion to release him from his contract.Jon Jones' deleted tweetsJon Jones' deleted tweetsCurrently, 'Bones' and the UFC are still engaged in a holding pattern regarding Jones's next fight in the octagon. As a result, there's no certainty whether a potential dream match between Jones and Ngannou would come to fruition.#1 Anderson Silva vs Chael SonnenUFC 148 Preview: Chael Sonnen WorkoutChael Sonnen is arguably the best trashtalker in the UFC and a pioneer of using Twitter as an instrument for dissing a rival fighter. One of his biggest targets was the legendary Anderson Silva.This is not much of a feud, however, as it was a one-sided affair with Chael Sonnen unloading a truckload of racist and xenophobic comments on then-UFC middleweight champion Silva and his camp."A.S. Your run is T- 70 days. I'm not a math teacher from Ohio, I'm a gangster from Oregon. Talk is cheap, it takes money to buy whiskey," Sonnen wrote in a now-deleted tweet.Where it got super dicey was when Sonnen started insulting Ed Soares, who was Silva's manager and fellow Brazilian."Ed, pray to whatever Demon effigy you prance and dance in front of with your piglet tribe of savages that I decide not to CRUCIFY you," Sonnen tweeted in 2010.Anderson just fired Ed Soares and replaced him with a Translation App he got on his phone for $14.95.— Chael Sonnen (@ChaelSonnen) July 22, 2010Sonnen also called Portuguese “half-step up from pig Latin” to insult his Brazilian foe. In the end, Silva would shut Sonnen up by submitting him in their first fight and stopping him via TKO in the rematch.