DETROIT — After a long day, Lions right tackle Penei Sewell returned home to a pleasant surprise.

His 2-year-old son, Malakai, was impersonating Sonic the Hedgehog — but not the video game character. He was mimicking Sewell’s Lions teammate, running back Jahmyr Gibbs.

“I got a Sonic fluffy toy for my son because he loves Jah,” Sewell said. “One day, I come home and he’s running with the toy, he goes, ‘DaDa, Uncle Jah.'”

Sewell’s toddler isn’t the only one who has taken notice.

Nicknamed after the 1990s video game characters, the 22-year-old Gibbs, aka “Sonic” because of his speed, and 27-year-old backfield mate David Montgomery, tabbed as “Knuckles” for his strength, have made a name for themselves as part of coach Dan Campbell’s “two-headed monster” backfield. Over the past two seasons, they have combined for 4,417 yards from scrimmage.

In Gibbs and Montgomery, the Lions have two players who could be feature backs for nearly any team in the NFL. But they say they have no issues splitting carries and have put aside egos and personal accolades in hopes of helping the Lions win the franchise’s first Super Bowl — a pursuit that continues Thursday against Montgomery’s former team, the Chicago Bears (12:30 p.m. ET, CBS).

They say they aren’t sure how their new nicknames were created. They only know that once the nicknames were brought to their attention online, they embraced them, even though the names aren’t perfect descriptions of the players’ styles on the field.

“I would say it’s pretty accurate, but I would say in some ways, we could change roles, depending on situations,” Gibbs said.

Sunday’s 24-6 win over the Indianapolis Colts was the most recent example of their productive partnership. Gibbs and Montgomery found the end zone a combined three times (two for Gibbs, one for Montgomery) and reached a number of milestones in the process.

The performance marked the 11th time the duo had each scored a touchdown in the same game (including the playoffs), which is the most such games by a running back duo in NFL history, per ESPN Research. And with Gibbs’ second score of the day, a 5-yard sprint late in the third quarter, he and Montgomery became the first duo in NFL history to score 10 rushing touchdowns each in consecutive seasons.

“It’s super dope to know that me and him are doing something real special and we just want to keep going and see where it ends up,” Montgomery said. “We’re trying to be in the history books and I’m saying in the Super Bowl … we’re trying to be in the history books, too, for what me and him can do together, so it’s special.”

Gibbs agreed.

“That’s what we’re trying to do,” Gibbs said. “But mostly we want that Super Bowl first and if we get that, I think everything else will come with it.”

SONIC AND KNUCKLES joined forces in the spring of 2023 and said there was an instant connection.

That March, Montgomery, a former third-round pick by the Bears in 2019, joined the Lions on a three-year, $18 million deal. A month later, the Lions selected Gibbs, a playmaker from Alabama, with the No. 12 pick before trading running back D’Andre Swift to his hometown Philadelphia Eagles.

“Since the first time I got here. The first time we started talking. I could tell he was different,” Gibbs said of Montgomery. “He wanted the best for me, and I wanted the best for him. Ever since then, we’ve been locked in.

“I don’t think it was a specific moment. We’re just like that naturally and for each other.”

The two like to engage in friendly competitions to push each other from week to week. After Sunday’s win, Montgomery was aware Gibbs (90 rushing yards on 21 carries vs. Indy) had pulled away with a team-high 886 rushing yards on 154 carries compared to his 632 yards on 145 rushes.

“Gotta go get him,” Montgomery joked.

They encourage each other as well. The duo combined for three first-half rushing touchdowns in a 42-29 Monday night victory over the Seattle Seahawks in Week 4. While getting dressed after the game, Gibbs said without hesitation they were the league’s best running back tandem and it’s not “close at all,” despite Montgomery starting in all four games until that point.

“We both can do everything, so it’s hard for defenses to scheme up against us,” Gibbs told ESPN. “I mean the production speaks for itself, too.”

Campbell has likened their relationship to that of siblings, saying it has pushed each player to become better.

“David and Gibbs are like brothers … David’s big brother and he’s not going to let anybody mess with him, that’s his guy,” Campbell said. “Now, he’ll mess with him, and if he does something wrong he’s going to let him know, but he takes him under his wing and I think they’ve elevated each other and he’s made Gibbs better and I think has helped him too.”

As for Gibbs and Montgomery, they say they’ve clicked because they share the same goal.

“We both want to win and we’re both selfless humans. Jah’s really selfless and he’s humble and I like to view myself the same way,” Montgomery told ESPN. “He’s special, bro. He’s elite and I believe he’s going to go down as one of the best to ever do it.”

CAMPBELL HAS ALWAYS envisioned having what he calls a “two-headed monster” in the backfield.

Before becoming Detroit’s head coach in 2021, the former NFL tight end witnessed the running back duo of Ron Dayne (781 yards from scrimmage) and Tiki Barber (1,725 yards from scrimmage) — known as “Thunder and Lightning” — help his 2000 New York Giants to a Super Bowl appearance against the Baltimore Ravens.

As an assistant head/tight ends coach with the New Orleans Saints in 2017, he also saw how coach Sean Payton utilized running backs Mark Ingram (1,540 yards from scrimmage) and rookie Alvin Kamara (1,554 yards from scrimmage), making them the first running backs to make the Pro Bowl from the same team in at least four decades.

He kept those examples in mind for Gibbs and Montgomery as he assembled the duo.

“To me, they’re the perfect combination,” Campbell said. “It doesn’t come any better, in my opinion. You’ve got everything you need out of those two players, run or pass game.”

Sunday’s game marked Montgomery’s 25th with the Lions. In that span he has scored 24 rushing touchdowns, tied for sixth most in NFL history by a player in their first 25 games with a team. Detroit is also 9-0 in games when both Gibbs and Montgomery rush for a touchdown.

“When you have a common goal and you have a chance to win, one of the things you have to do is you have to be at your best at all times,” Lions assistant head/RBs coach Scottie Montgomery said. “And one of the ways we’re able to keep them at their best is to split some of the things that they do.”

But being part of a backfield duo isn’t always easy. Ingram said there are pros and cons to splitting carries with another elite running back. Among the pros: career longevity and fresher legs down the stretch. Among the cons: sacrificing personal accolades, such as rushing titles and statistics.

“You have to be prepared to maximize your opportunities because you don’t know how many touches you will get or when the touches will come. You have to stay locked in and loose on the sideline and active in the games even if you aren’t getting consistent touches, which can be a challenge and take some getting used to,” Ingram said. “Also, when you are the RB1 and feature back, you know you wake up game day and you will be out there with a chance to get into a flow, get into a rhythm.

“But when you rotate in and out based off personnel packages, not only is it challenging to get into a flow and rhythm but it also gives defenses a key on tendencies when one player is in the game versus another, so the coaching staff must self-scout so they aren’t giving away tendencies in how each back is being used.”

Former NFL running back T.J. Duckett formed a successful tandem with Warrick Dunn as Atlanta Falcons teammates from 2002-2005, where they combined for 6,296 rushing yards and 53 regular-season touchdowns in their time together. Each accepted their roles: Duckett thrived in short-yardage situations while Dunn was a playmaker. But Duckett calls successful partnerships “very rare” in the NFL.

“At the end of the day, you’re taking food off people’s table,” Duckett said. “The thing with Warrick was he was trying to make me better even though that could’ve jeopardized his spot. … It worked out that way, but I was in other rooms and the dynamics were completely different.”

In Detroit, Gibbs and David Montgomery say they’re committed to keeping a good thing going.

And for any doubters who may feel like their partnership won’t last, Gibbs issued a warning.

“If y’all think we’re ever going to turn on each other or are against each other, it’s not going to work,” Gibbs said. “Y’all won’t get us, so just letting y’all know that now, so don’t try it.”