The nickname "Pop" stuck because, even after that first time Isiah Pacheco "popped" an opponent while playing in Vineland, New Jersey, youth leagues, it kept happening.

Now an NFL running back for the Kansas City Chiefs, not much is different about “Pop.” His running style − arms pumping, knees elevating, feet stomping − has become Internet meme fodder.

"The funniest one, I thought," Pacheco told reporters Wednesday, "they say 'You run like you bite people.' I ain’t no zombie."

The 24-year-old does run like he is trying to mummify the opposing defender who has the misfortune of stepping in front of his path.

"For me, it’s just being determined and understanding that I have a goal to achieve," Pacheco said.

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The goal is a second Super Bowl in as many seasons. Beware whoever gets in his way.

The way Isiah Pacheco runs: 'Been doing this a long time'

Dan Russo was in his first season coaching the Vineland High School football team in 2013. The coach of the youth team Pacheco played for, “The Blitz,” said Russo had to check out this eighth-grader.

"He was unbelievable," Russo told USA TODAY Sports. "That’s an understatement. He’s been doing this a long time."

By then, Pacheco had the nickname “Pop” for a few years. Russo needed him to be more than a bruiser. He needed a quarterback.

In Russo’s system, the best athlete played the position. Pacheco was a four-year starter at quarterback for Vineland and also played defensive back. (In the spring, he showcased his arm strength as an outfielder for the baseball team; he also hit .475 his junior year.) So Pacheco’s touchdown in the wild-card round victory over the Miami Dolphins two weeks ago looked familiar to Russo, who texted him saying that he loved seeing the 5-foot-10, 216-pound back lined up in shotgun.

"And he’s writing back saying he’s laughing his (butt) off," Russo said.

As a 145-pound high school freshman, Pacheco ran the same way he does now.

"He’s always trying to prove himself and prove his toughness," Russo said.

Russo pleaded with him to avoid contact if he was near a sideline and it was clear he wouldn’t gain additional yardage after contact. Pacheco wasn’t hearing it.

"He used to take (defenders) on, try to run them over," Russo said.

Russo added: “Not only did he make great plays, but our kids were better because they believed in him.”

Ryan Day and Urban Meyer tried to convince Pacheco to attend camp at Ohio State. But the South Jersey native was intent on staying close to home and committed to Rutgers, the first school to offer him a scholarship. He enrolled early ahead of his freshman season, just as Nunzio Campanile was joining the program as running backs coach.

"Everybody’s always talking about how he runs," Campanile, now the quarterbacks and offensive associate head coach at Syracuse, told USA TODAY Sports. "That’s how he worked in the weight room. That’s how he worked in the meeting room. He’s a great competitor. And he loves football and it’s evident in everything that he does.

"What you see on game day is who he is all the time. And that is really, to me, why he’s been so successful."

Another love of Pacheco’s, according to his former coaches, is his family. Which makes the heartbreak he endured as a teenager even more tragic.

Family tragedies fuel Isiah Pacheco

In January 2016, Pacheco’s brother, Travoise Cannon, was killed in a stabbing in Bridgeton, New Jersey. Pacheco told NJ.com in 2019 that Travoise encouraged him to play football as a kid. He dedicated the 2016 season, his junior year at Vineland, to his brother’s memory.

"It changed everybody's life," Pacheco's mother, Felicia Cannon, told the Big Ten Network.

Of his four siblings, Pacheco was closest with his sister, Celeste Cannon. She was like a second mother to Pacheco and was a mother of three of her own. She was murdered on Sept. 20, 2017 in Millville, New Jersey, by the father of one of her children.

"That did something to him," Pacheco's father, Julio, told the Big Ten Network. "Took a chunk of his heart."

Russo told Pacheco to take as much time as he needed and to not worry about football.

"He’s like, ‘No coach. I’m ready to go. I’m ready to play’… he was adamant about playing," Russo recalled.

Pacheco played three days after Celeste’s death and ran for 222 yards and a touchdown to lead Vineland to a 42-6 win over Egg Harbor Township. On the day of Celeste’s funeral, Sept. 29, 2017, he suited up and ran for 157 yards and three touchdowns in a 60-6 victory against Cumberland Regional.

"Having an opportunity to play ball, it helps me a lot not worrying about the tragedies that happened," Pacheco told NJ.com. "It makes me want to go harder."

Pacheco has tattoos on both arms to honor his departed siblings.

"I play football for them," he said.

Russo said Pacheco has a close relationship with his parents, Felicia Cannon and Julio Pacheco.

"He’s just a great representative of his family," Campanile said, "because he’s a really good person."

Running angry? 'Absolutely'

Following a four-season collegiate career, the Chiefs selected Pacheco in the seventh round of the 2022 draft, 251st overall. Rutgers head coach Greg Schiano, who took over in 2020, harped on situational football in hopes of connecting with the roster he inherited, Campanile said. Pacheco took the lessons to heart.

"He really bought into that and really worked hard to make himself a student of the game," Campanile said.

Pacheco’s well-rounded skills made his transition to Andy Reid’s offensive scheme easier. At the end of his college career, Pacheco tried to better understand protections, Campanile said. It helped him go from seventh-round pick to a starter scoring a touchdown in the Super Bowl within one year’s time.

In Arizona last year for the Super Bowl, Russo saw how Pacheco mixes well with Chiefs quarterback Patrick Mahomes, tight end Travis Kelce and other team leaders.

"He’s just electric," Russo said, "and everyone feeds off his electricity."

Pacheco started 11 games as a rookie in 2022 and was a key cog for the Chiefs' Super Bowl run. He missed three games in 2023, rushed for 935 yards on 4.6 yards per attempt and had nine total touchdowns.

"That guy is coming downhill. … He’s rolling, and it’s going to be a big challenge for us to deal with him, because he’s as physical as a runner as there is in the league," Ravens head coach John Harbaugh said ahead of the AFC championship game.

On Wednesday, Pacheco was asked if his running style could be described as "angry."

"Absolutely," he replied.

But it’s more than that to “Pop.”

"Leaving it all out on the field," Pacheco said, "with no regrets."