College football fans might have seen Halley's Comet more often than they watched a quarterback start for one team, transfer, and then start against his old team.

Times have changed. A study by The Athletic this summer revealed that 84 percent of quarterbacks in the Class of 2021 finished their career somewhere other than where they signed out of high school.

With greater movement and immediate eligibility, college football has a new tradition: the quarterback revenge game.

Jackson Arnold will lead Auburn to Oklahoma, his old school, this weekend, in perhaps the biggest "revenge game" of the regular season. Auburn and Oklahoma finished with losing records a season ago, but both come into Saturday undefeated and ranked. The winner can start dreaming of a run to the SEC championship and College Football Playoff.

Arnold, a five-star recruit out of high school, struggled as a first-year starter at OU last season while throwing to a receiving corps riddled by injuries. He threw for just 1,421 yards and was benched midseason for true freshman Michael Hawkins.

Arnold landed with the Tigers this offseason and has a talented duo in Cam Coleman and Eric Singleton as targets. He's thriving, with eight touchdowns (four passing, four rushing) through three games, while Oklahoma is also on the rise behind Washington State transfer QB John Mateer.

Just last week, former Tulane star Darian Mensah returned to New Orleans with Duke, where he earned a multimillion-dollar contract. Tulane coach Jon Sumrall held no ill will toward his former passer, but the Green Wave won 34-27, behind four rushing touchdowns from new quarterback Jake Retzlaff.

Auburn-Oklahoma won't be the last so-called revenge game this season. Dequan Finn was named MVP of the MAC in 2023 while leading Toledo to a conference title. He left for Baylor but suffered an injury and lost the starting job to Sawyer Robertson. Now, he's back in the MAC at Miami (Ohio). The Redhawks will host Toledo on Nov. 12.

Here's a brief history of some notable revenge games in past years, starting with a trip back in time:

George threw for four touchdowns and 15 interceptions (yes, really) as a true freshman at Purdue in 1986 but transferred after coach Leon Burtnett resigned. Two years later, he won the starting job at Illinois and easily dispatched the Boilermakers 20-0, completing 15 of 34 passes for 152 yards and a touchdown that gave the Illini an early 7-0 lead. From late in the first quarter until midway through the third, he completed just 3 of 15 passes for 18 yards.

"I had a lot of dreams about this game," George said after the win. "Some of the dreams came true. Some didn't."

A year later, George beat the Boilermakers again, this time in West Lafayette. Fans booed. One threw a tennis ball at him in the third quarter and he almost caught it, according to newspaper reports. He completed 24 of 42 passes for 254 yards and a touchdown in a 14-2 win without an interception or a sack.

Berlin, a five-star recruit, was the nation's No. 2 prospect when he signed with Steve Spurrier and Florida. He was mostly stuck behind Rex Grossman, but helped the Gators beat Maryland in the Orange Bowl to end the 2001 season after Grossman was suspended for a half.

He left after the season for rival Miami, and after sitting out the 2002 season, began his home career at Miami with a game against the Gators. Florida guard Shannon Snell said ahead of the game he hoped the Gators' defense would hit him in the mouth and make his mouth bleed.

Florida raced to a 33-10 lead and looked ready to end Miami's 33-game winning streak. But Berlin rallied the Hurricanes for a 38-33 win and finished with 340 yards and two scores on 27-of-41 passing. On his way off the field, he did a mocking Gator chomp before a throat slash gesture and found Snell on the field after the comeback.

"You want to hit me in the mouth now?" Berlin asked his former teammate.

Berlin would move to 2-0 against Florida by defeating the Gators in the 2004 Peach Bowl a year later.

Mayfield walked on at Texas Tech in 2013 and became what's believed to be the only walk-on true freshman to start a season opener for a major-conference team. But after the season, he transferred to Oklahoma and sat out a season. Texas Tech fought and won a battle that prevented him from being immediately eligible, leading Mayfield's father to call Texas Tech coach Kliff Kingsbury a "scoundrel."

He won the starting job in 2015, helping OU to a 63-27 win over the Red Raiders in Norman. In 2016, made his long-awaited return to Lubbock, greeted by plenty of Texas Tech fans wearing black "traitor" shirts and chanting "f- you Baker." Mayfield won a legendary duel with Patrick Mahomes, throwing for five touchdowns and 545 yards in a 66-59 win.

He finished his career 3-0 against Texas Tech after a 49-27 win in 2017.

Franks spent two seasons as Florida's starter but broke his ankle early in the 2019 season and left for Arkansas after Kyle Trask took hold of the job. Under first-year coach Sam Pittman, Franks traveled back to the Swamp a year later and completed 15 of 19 passes for 250 yards and a pair of scores, but the Hogs weren't competitive, losing 63-35.

Coan was Wisconsin's starter in 2019 but left to finish his career at Notre Dame after an injury kept him off the field for all of 2020. In 2021, he led Notre Dame against his former team at Soldier Field in Chicago. He completed 15 of 29 passes for 159 yards and a touchdown, but suffered an injury and backup Drew Pyne finished the 41-13 Irish win. Wisconsin led 13-10 early in the fourth quarter after Coan's injury, but Notre Dame scored the game's final 31 points, thanks to four Badgers turnovers and a missed field goal in the final quarter.

Shough spent most of 2020 as Oregon's starter but left for Texas Tech after some late-season struggles. A little more than two years later, the Ducks found their way to Lubbock. Shough threw three touchdown passes and completed 24 of 38 attempts, but threw a trio of interceptions in a 38-30 loss. Texas Tech led the game by nine entering the fourth quarter, but in the final minute, with the Red Raiders driving at midfield and trailing by one, Shough threw a pick-six to Jeffrey Bassa.

Gabriel started a season and a half for the Knights and transferred to Oklahoma after an injury-shortened 2021 season. He threw for more than 6,800 yards and 55 touchdowns in two seasons with the Sooners, and in 2023, his former team came to Norman as a new member of the Big 12. Gabriel threw for 253 yards and three touchdowns, and the Sooners survived a back-and-forth game with a 31-29 win after UCF failed to convert a two-point conversion with 1:16 to play.

Hartman started almost four full seasons for the Demon Deacons but left for Notre Dame as a graduate transfer to play one last season of college football. Late in the season, he faced his former team, which finished the season with eight losses in nine games.

Wake Forest didn't put up much of a fight. Hartman threw for four touchdowns in a 45-7 Irish victory.

Armstrong was a three-year starter and two-time captain for the Cavaliers before following offensive coordinator Robert Anae to NC State after Anae left and Armstrong struggled in 2022. He'd already set school records for passing yards and touchdowns. The reunion didn't recapture their Charlottesville magic, but NC State went 9-4 and Armstrong completed 15 of 30 passes for two touchdowns and an interception in a 21-14 win over UVA on his former home field.

Unlike the others, Ewers never threw a pass for his first school, but he signed with the Buckeyes as the nation's No. 1 overall recruit in the Class of 2021. After a season on the bench, he transferred to Texas, returning to his home state. In the final game of his career, he faced the Buckeyes in the national semifinal.

He threw for 283 yards on 23-of-39 passing with a pair of scores, but with Texas trying to tie the game, Jack Sawyer -- who arrived at Ohio State alongside Ewers as the nation's No. 5 prospect -- sacked him, scooped up the fumble and returned it 83 yards for a score to seal the win and keep Ohio State's national title run alive.

As Jackson Arnold takes Auburn to Oklahoma, a brief history of QB 'revenge games'