There will never be another fighter quite like Chael Sonnen.
The 42-year-old retired from MMA competition Friday after losing to Lyoto Machida at Bellator 222 via second-round TKO. Sonnen wraps up his career with a 30-18-1 record, including wins over Michael Bisping, Mauricio "Shogun" Rua, and Wanderlei Silva.
Never one to turn down a fight, Sonnen's resume includes battles with the likes of Anderson Silva (twice), Jon Jones, and Fedor Emelianenko. Here's a look at five key moments in his career.
Perhaps the most memorable moment of the UFC's first-ever trip to Vancouver, British Columbia, at UFC 115 didn't even occur on fight night.
Sonnen, fresh off his No. 1 contender victory in the middleweight division over Nate Marquardt at UFC 109, took aim at Silva's longtime mentors - Antonio Rogerio and Rodrigo Nogueira - during the UFC 115 Q&A. This served as one of the biggest moments in the buildup to his title fight against Silva at UFC 117.
"A black belt from the Nogueira brothers is like saying I got a free toy in my happy meal," Sonnen said.
Closing as a 3-1 betting underdog, not many were giving Sonnen a chance against middleweight champion Silva at UFC 117.
Instead, Sonnen put on a clinic with his wrestling against "The Spider," putting himself ahead on the judge's scorecards heading into the fifth round. However, Silva shocked the crowd in the opening moments of the final round by ending the fight with a triangle armbar.
Sonnen may have lost his opportunity at UFC gold, but he gained notoriety around the MMA community for his performance. This was easily one of the most memorable fights in UFC history.
It's rare to see a fighter earn a title shot off a loss, but Sonnen was able to accomplish that feat at UFC 159.
After losing to "The Spider" in their rematch at UFC 148, Sonnen talked his way into a title shot at Jon Jones's light heavyweight championship. "Bones" made quick work of Sonnen, stopping him in the first round via TKO.
However, during his post-fight interview with Joe Rogan, it was revealed that Jones broke his toe in the opening stanza. Had Sonnen survived Jones' early onslaught into the second round, the doctors would've ruled the match a TKO victory for the Gracie Barra Portland product.
Like many of his fights, Sonnen closed as a betting underdog when he faced Mauricio "Shogun" Rua in the main event of UFC Fight Night 26 in August 2013.
Sonnen made quick work of Rua, handing the Brazilian fighter his first submission loss since September 2007. The win propelled Sonnen to another pivotal matchup in the division against Rashad Evans at UFC 167, where he ended up losing via first-round TKO.
Following a two-year suspension for a failed drug test, Sonnen surprised many by leaving the UFC to sign with rival promotion Bellator.
His promotional debut was forgettable, losing via first-round submission to Tito Ortiz at Bellator 170 in January 2017. However, "The People's Champ" would get a shot at redemption a few months later, facing longtime foe Wanderlei Silva at Bellator NYC in June 2017.
While the matchup itself wasn't entertaining, Sonnen made history by being the main event of Bellator's inaugural New York event and earning his first win since August 2013 in the process.