There’s something organic about the way it all happened. A 60-year-old Buffalo man drove around 90 minutes to just outside of Rochester to buy a Body Opponent Bag — now called “Bob the dummy” — on Facebook Marketplace two days before the city’s first playoff game in 15 years. A group of younger Sabres fans known as the Blade Gang veered around KeyBank Center before that same April afternoon.

And when Nick Mastrocovo moved his dummy — donning a Bruins jersey for the Sabres’ first-round opponent — closer to the Blade Gang during the pregame festivities April 19, one member landed a punch. Everyone erupted. Another member tackled the dummy from behind. A viral moment was born. Mastrocovo and his cousin returned for Game 2 in referee jerseys, just in case something got out of control after the added attention. The Blade Gang traveled to Boston for road games. Playoff hockey in Buffalo suddenly had more than a pulse.

It rapidly became the epicenter of the tournament.

“I don’t think that they go viral without the dummy … and I don’t think the dummy gets as much love without them,” Mastrocovo told The Post.

For more than a decade, the intersection of Washington and Perry was dormant this time of year. Seasons unofficially ended in December. Aprils were about coaching changes. The Sabres were the punch line on national television. In December, when Buffalo sat in last place in the Eastern Conference, that became the case again, but a historical turnaround that led to the Atlantic Division title has now reached the second round of the postseason for the first time in 18 years — with Game 1 of the second-round series against the Canadiens set for Wednesday in Buffalo.

And at the center of it has been the Sabres fans who “are just nuts,” Mastrocovo said.

“You’d always go out in these stores in Buffalo and you see people wearing [Alex] Ovechkin shirts or [Sidney] Crosby shirts,” Mastrocovo told The Post. “Someone wore something Sabres, the joke was, ‘Oh did you lose a bet?’ And now, you see these kids wearing Sabre jerseys.”

So for the first time since the 2006-07 season, there’s a reason for fans to descend on downtown Buffalo, weaving through the highways and streets where — with a good gust of wind — you can smell the Cheerios from the General Mills factory.

The Sabres are one of 10 NHL teams who haven’t won a Stanley Cup, though they came close in 1999, and for as much as Josh Allen and Bills Mafia and folding-table shenanigans have shaped Buffalo’s sports reputation in recent years, it has always been a hockey city, too.

Mastrocovo’s mom helped clean the visiting locker room at the old Buffalo Memorial Auditorium, he said. His two hamsters growing up were named Rick and Martin — after one of the members of the Sabres’ French Connection line. Those were links to the initial days, when they made the Stanley Cup Final in just their fifth season, and the Sabres have been a part of his entire life. They advanced to the Eastern Conference finals in 2006 and ’07, but fell short again.

Some of those runs were expected. This one, though, wasn’t.

Alex Tuch, who collected 33 goals during the regular season and another four during their first-round series, hinted at what would happen with fans in the playoffs. “I hope they have a lot of police officers and firemen on duty,” he said on TNT after the Sabres officially clinched a spot in the tournament, “because I feel like the whole city’s gonna burn down. It’s gonna be awesome.”

Ticket prices have skyrocketed. Local stores started prioritizing Sabres merch again. Watch parties at Canalside, the downtown waterfront, made cameos on broadcasts, capturing the pent-up energy. When singer Cami Clune’s microphone stopped working during the Canadian national anthem in Game 5, fans inside KeyBank Center picked up with the words and created a crescendo that spread across social media.

When the Sabres returned home from Boston after clinching the first-round series in Game 6, fans gathered at the airport to greet the team. The dummy, still in a Cam Neely No. 8 jersey, was there, too. Players recorded the scene as they drove by. And for around 30 minutes each pregame, Mastrocovo’s dummy entered the spotlight. Fans wanted pictures as it rolled up the street.

It took a beating, he joked. He messaged the woman he bought it from again and said, “Hey, I’m not sure if you caught anything online, but I just want you to know what happened to your dummy.” 

“This is the best marketplace sale I’ve ever had,” he recalled her replying.

The question becomes how long this will all last. Behind forward Tage Thompson (40 regular-season goals) and defenseman Rasmus Dahlin (74 points) and a goaltender in Alex Lyon who became the starter in the middle of the Bruins series, their season could last until June.

Mastrocovo thinks it’s all sustainable for future seasons, too. For now, they’re guaranteed four more games against the Canadiens. For two of those, Mastrocovo’s dummy will have a plain, red Montreal jersey on — he has a Guy Lafleur one but wanted to be respectful.

The fans, and the spectacle that the dummy and the Blade Gang and the watch party creates, will be at the center of everything.

“It’s just balls to the wall, 100 percent, let’s go,” Mastrocovo said.