The accounts of the events of Aug. 16, 2008, conflict slightly, a little more blame on this side, a little more accusation on that -- in Brad's telling, there was hitting from both brothers -- but there is one thing that has stood the test of the decade-plus since the incident occurred: the conclusion. As Jeff and Brad rolled up the driveway to the house they were living in at the time, Brad started back up with the punching.
"He thought it was hilarious," Jeff said. "He was really hurting my leg, so I basically said, 'You do that again, I'm hopping out of the car'."
[RELATED: Complete Bruins vs. Maple Leafs series coverage]
Brad didn't stop.
Jeff put the car in neutral -- Brad remembers it as first gear -- and pulled the keys out as he jumped out of the Jeep. He thought the car would just stop, with Brad still inside. Instead, it kept rolling, slowly, toward the garage. Brad now wonders why he didn't just pull the emergency brake. But he didn't, and in slow motion the car inched forward, a horror movie happening in front of the brothers.
"The thing went right through my parents' garage door of their house and it crumpled right over his hockey gear," Jeff said during an interview in May. "It crumpled right over my parents' new lights -- they were building a house -- and it went right over their lights and smashed all their lights and hit the back wall.
"And Brad turned to me and looked at me and he goes, 'Mom and Dad are going to kill you.'"
The story makes at least one thing clear: Brad Marchand is the scorpion in the old fable.
The scorpion asks a frog to carry him across a river. The frog is afraid that the scorpion will sting him because, after all, he's a scorpion, to which the scorpion explains that, should he do that, they would both drown. So why would he?
It seems like a logical argument to the frog, who agrees to take him across the river. Halfway there, the scorpion stings him. They're both drowning when the frog asks the scorpion why he did it.
"I couldn't help it," the scorpion says. "It's in my nature."
Which is exactly how best to explain Marchand, as even he agreed, when told the fable.
"If you look at some things that have happened, it's always an act-first, think-later mentality," Marchand said. "I haven't really ever had too many cares and just kind of did what I did, so yeah, I think that's definitely part of it. Kind of dealt with the consequences later. You do it and you don't ask. You ask for forgiveness rather than permission."
And that's the problem with declaring Marchand rehabilitated as the Bruins get set to face the Toronto Maple Leafs in the Eastern Conference First Round, with Game 1 of the best-of-7 series at TD Garden on Thursday (7 p.m. ET; NBCSN, CBC, SN, TVAS, NESN).
That's the problem with crediting fatherhood or age or a leadership role to his better sense of responsibility. It's still there in Marchand, still deep down, still part of him, even though he may have cleaned up his act, for the most part, this season in the wake of two incidents of licking opponents during the 2018 Stanley Cup Playoffs.
Those moments, including one against Toronto in the first round, saw him get reprimanded by the NHL and left him rather contrite after Boston's season ended, but there's always the chance that on the next shift, in the next game, the scorpion will emerge.
"That's probably true," Bruins center Patrice Bergeron said. "I think that's accurate. He's one of those guys that [when] he's got something on his mind, he's going to stick to it, even if the result is not always even to his advantage."
Video: BOS@CBJ: Marchand buries loose puck from doorstep
If you ask Marchand, this is how he's always been, "a little devious," to use his words. And for a long time that didn't matter. Or it mattered in a positive way, in getting him into the NHL in combination with his prodigious talents.
But it has become less of a joke and more of a distraction as his star has risen, as those around Marchand have done their best to tamp down on the scorpion's impulses. He has tried harder. They -- including teammates Bergeron, Zdeno Chara and David Backes, in particular -- have tried harder.
"I think he takes a lot of pride now in knowing how good he can be offensively," Boston coach Bruce Cassidy said. "Maybe before it was more about an agitating mentality. I read a quote somewhere where he said he's too tired now to be an agitator, so I thought, you know what, we'll just keep playing him. If that's what it takes to keep him going on the ice, because look at him, when he's on the ice, he's deadly."
That is exactly what Marchand has been this season, reaching the 100-point mark (36 goals, 64 assists) for the first time in his 10 NHL seasons. The 30-year-old finished tied for fifth in the NHL in points and was one of six players to hit triple digits, along with Nikita Kucherov (128), Connor McDavid (116), Patrick Kane (110), Leon Draisaitl (105) and Sidney Crosby (100).
And so far, he has remained on the ice; he played 79 of the Bruins' first 80 games, missing one because of an injury, not a suspension, before being rested for the final two regular-season games.
Though Marchand's parents didn't necessarily encourage his behavior, they also didn't exactly discourage it. Which might have been what was going through Kevin Marchand's head when he pulled up to the house and saw the crumpled garage door, the lights in shards, the mess his son had made.
"He just gets a rise out of getting under [people's] skin," said Jeff, who is 15 months younger than Brad. "He's always been like this."
He still is. Mostly.
"Compared to where I was early on, I think I'm a lot better in a lot of areas," Marchand said. "But it's tough to change the stripes of a zebra. It's not that easy."
Video: BOS@CBJ: Marchand earns 100th point on Pastrnak goal
And forgiveness has been harder and harder to find.
He brings up 2016-2017 when, on the verge of his first 40-goal season, he was suspended for the final two games of the regular season for spearing Tampa Bay Lightning defenseman Jake Dotchin. He finished with 39 goals.
"I thought I was pretty good that year," Marchand said. "So you can be perfect until the last game, the last second of the last game, and it takes one split second to change the entire feel of the season. That's the way it is. One incident can ruin a year's worth of hard work.
"So, yeah, there's been a little more of a conscious effort, but I'm not going to say I'm better or I'm good or I'm out of hot water yet. It's something I'll always have to be aware of the rest of my career. I'll be on thin ice from here on out."
These days, he tries to catch himself. He tries to think. He tries to calm down, to listen to his teammates, to become aware of the emotions.
"Maybe paying attention is the biggest thing that I've started to do," Marchand said. "Before, I got in trouble, I got in trouble. It wasn't a big deal. I didn't really care. I played the game the way I played the game and whatever happened, happened. I was in the NHL. So I felt good about where I was at and I just kind of played. Now it's a little different feeling and situation, so I want to make sure the longevity is there, that I'm not getting pushed out of the League because of stupidity."
He tries not to give in to his baser instincts. But he knows they'll always be there, that another stumble is potentially just one shift away. He hopes not, but he knows the possibility remains. He's realistic about the situation.
He is the scorpion, after all.