The surging Brooklyn Nets face the first-place Boston Celtics at the Barclays Center on Thursday night, and Mr. Whammy, a much-loved fan favorite, will be parked under the Celtics basket during the first half. Wearing a custom Nets jersey over a red shirt, the octogenarian will shout and gesture behind the basket, trying to hex the opposing player into missing his foul shot. He’s been a fixture at Nets games since the team moved to Brooklyn in 2012.

During a recent Nets home game against the San Antonio Spurs, I got to watch Mr. Whammy in action, up close, from a seat nearby.

The moment the whistle blows for a foul shot, Mr. Whammy, all 5-foot-7-inches of him, springs into action. He does his best to distract and put the whammy on that player, his pinky and index fingers extended and shaking on both hands. He even has his own polite trash talk.

“Okay, three! Look at me, look at me, three,” he calls out as Spurs guard Keldon Johnson, No. 3, tees up for his first shot. He sinks it.

Mr. Whammy is undeterred. “Look at me, look at me. Here I am, here I am. Miss!”

Johnson shoots — and misses. "I got one!" Mr. Whammy exclaims.

Brooklyn Nets superfan Bruce Reznick, "Mr. Whammy", attempts to distract Ben McLemore of the Houston Rockets as he attempts a free throw against the Nets.

An hour before the game, we chat in a nearby tunnel off the court. Mr. Whammy is Bruce Reznick, a Brooklyn native who’s been attending Nets games since the team was in New Jersey, accompanied by his wife, Judy, a.k.a. Mrs. Whammy. They met during his senior year of high school, and have been together ever since.

“I'm 86 years old,” Reznick said. “Feb. 1, I'll be 87 years old. And having the best time of my life, thanks to the Nets.”

Judy helped support Reznick through law school and he still practices in Brooklyn, with his son – all three of his kids are lawyers – and his wife is the office manager. But Mr. Whammy’s passion is the Nets. He got season tickets 25 years ago, and started putting the whammy on opposing players a few years later.

“So now, I get a little popularity in Jersey,” he said, “and I get a call one day from this beautiful young lady going to University of Michigan, and she says, 'I saw you on TV.' That's all I had to hear. Now, I always wore a red shirt. I still wear my red shirt.”

Mark Jackson, the former Knick who became a broadcaster, actually used to call Reznick “Red Shirt.” And New Jersey Nets players like Vince Carter and Jason Kidd have loved him, in part because he has an unbreakable code: "I don't whammy any ex-Nets, if they played for only a day,” he said.

After Kidd was traded to the Dallas Mavericks, he explains, that code of honor prompted veteran Nets sportscaster Ian Eagle to coin a memorable name. “Jason gets up to take a foul shot, and I don't give him the whammy," Reznick said. "Ian Eagle on national TV said, 'Hey, look at that: Mr. Whammy's not giving Jason Kidd the whammy.' He gave me the name just like that, on national TV. And it stuck.”

In his self-appointed role as Mr. Whammy, Bruce Reznick lives by a personal code: "I don't whammy any ex-Nets."

Eagle, a Nets sportscaster for 29 years, says Reznick was hard to miss behind the basket. “It looked like he was trying to give the shooter the whammy with his pointing and gesticulations,” Eagle said. “So that's when the nickname was born. And it's been a part of Nets lore ever since.”

Fans recognize the local celebrity's love for the Nets, Eagle notes. “He genuinely cares about the team, and maybe more importantly than that, he cares about hexing the other team," he said. "The numbers don't lie. And Mr. Whammy keeps his own personal statistics.

"How do I know this? Because he will leave his stats on numerous voicemails on my cellphone," Eagle added, laughing.

Indeed, according a recent post on the Nets’ Twitter page, opposing teams only have a 70.3 foul shot percentage in Brooklyn – about 8 points lower, on average, than across the rest of the league.

“Some opposing players, most notably LeBron James, have lodged complaints," Eagle said. "But the Nets consistently stand by their man.”

Not that Mr. Whammy wishes ill on opposing players. “I tell every player, 'I wish you good luck, success and may you miss your foul shots,' right to their faces,” Reznick said. And the Nets, past and present, appreciate him in return. When Jason Kidd was inducted into the Basketball Hall of Fame, he invited Mr. and Mrs. Whammy as guests.

More recently, superstar Nets forward Kevin Durant, who has rarely interacted with the Nets superfan, came close to greet people seated nearby. "And when he finishes, he kisses Judy on the cheek,” Reznick said. “And she hasn't bathed that side of her face in a month-and-a-half already! And he shakes hands with me – I thought I'd drop dead right then and there.”

Mr. and Mrs. Whammy take time to greet their admirers during games, radio reporter Jeff Lunden (center) included.

The thing is, everybody loves Mr. Whammy. Before the game, ushers, vendors and security guards give him fist bumps. Anytime there’s a break in the action, fans approach Mr. and Mrs. Whammy to take selfies.

“We have such love from the fans,” Reznick said. “They love us as much as we love them, and we're blessed.”

Mrs. Whammy addresses me, with my recording equipment: “After you turn that off, if you want to take a picture with us so you can show everybody.”

Of course! Who wouldn’t? Oh… and the Nets crushed the Spurs, 139-103. The whammies were working well that night.