The Butt Army has invaded Denver. Resistance is futile. You cannot hope to defeat it, Broncos Country. So might as well enlist.

“The Butt Army? We’re growing,” tight end Jake Butt told me Wednesday. “It’s big. And getting bigger.”

Pun intended.

Catching his first NFL pass against Seattle, more than 20 months after painfully ripping apart his knee on his final reception in college at Michigan, was a special moment. The Butt Army had returned to active duty. How good did it feel? I sought out the commander in chief to find out.

“Hi, I’m Head Butt,” said the father of Denver’s tight end, offering me a handshake in the bowels of the stadium.

The Head Butt? Well, I already knew his title, because it was printed on his uniform.

Amid a sea of fans wearing orange and blue during the Broncos’ season-opening victory, Rob Butt was easy to spot. He donned his son’s No. 80 at the game, cheekily declaring his parental pride with “HEAD BUTT” emblazoned in big, block letters on the back of the customized Broncos jersey.

When the family name is Butt, there’s only one way to survive the third grade, much less make it to the NFL. “We taught our kids at an early age to just have fun with it,” Rob Butt said.

Standing proudly alongside him Sunday were two of the army’s most decorated soldiers. Both wore No. 80. “LIL BUTT” was Zac, younger brother of the tight end. And “MAMA BUTT was Meg, who gave birth 23 years ago to a child so huge she asked doctors to give Jake genetic tests, wondering if he might actually be a giant.

The Butts cannot lie. They like it big. You know how some households contain enough siblings to form a basketball team? Well, Rob Butt has seven brothers and sisters. Meg Butt is one of 16 children.

“I have cousins I haven’t even met,” Jake Butt said.

At last count, there were 53 cousins. Basketball team? This is a family big enough to form, well, an army.

On Butt’s way to becoming a two-time All-American at Michigan, the army became a phat and happy thing. Anyone who loved Butt showed up to games wearing his jersey, adorned with word play on football’s funniest, punniest name.

But can we be serious for one minute? While Butt couldn’t get on the field as a Broncos rookie in 2017 during rehabilitation from a severe injury, there was an army of supporters walking alongside him on the long road to recovery.

“During my comeback, how much has my family, my teammates, my coaches and my supporting cast meant to me? Everything,” Jake Butt said.

He caught two passes against the Seahawks, and rumbled 22 yards into the red zone on Denver’s winning touchdown drive.

“It was just good to see him out there on the field,” Rob Butt said, “running and enjoying himself again.”

When the Broncos travel later this season to play the Bengals, not far from the family’s home base in Ohio, at least 100 members of the army will mobilize for a friendly takeover of the stadium in Cincinnati.

The Butt Army has launched an ambitious plan to conquer the NFL world, one city at a time. Might as well start here. It’s Raiders Week in Colorado. Jake Butt is looking for new recruits to kick the Raiders’ booty. He will get creative to lure volunteers.

For example: There are undoubtedly long-time Oakland fans feeling a sense of deep betrayal, reeling from the trade of linebacker Khalil Mack and angry because their local team is itching to leave the Bay Area for Las Vegas. The Butt Army has an idea. Trade in that silver and black No. 52 of Mack for a brand new orange No. 80 jersey

“There are probably some 5-year-old kids who are Raiders fans that I can win over, after they see me and say: ‘Oh, man. His name is Butt! Really? I like him. That’s the jersey I want,’ ” said Jake Butt, reaching out to jilted Oakland supporters looking for a better team to love.

The Butt Army wants you.