It's a twist of the spine so sharp and swift, it makes his colleagues cringe.
"I don't know how he doesn't rip his back or his spine doesn't become disjointed," said Major League umpire Ted Barrett.
When Tom Hallion deems a pitch deserving of being denoted a third strike, he does so with conviction. The baseball settles into the catcher's glove, and Hallion rises from his crouched position, coils his torso nearly 180 degrees, swivels his agile knees, hips and feet and delivers a spirited fist pump to signal the end of the batter's trial at the plate.
"I don't know how he doesn't dislocate some parts of his body," umpire Dale Scott quipped. "It's so extreme and almost violent when he calls strike three. Maybe he'll have to have a back or a hip replacement."
Said umpire Lance Barksdale: "That's too much effort, what Tom does. A couple years ago, every time he rang somebody up, we would all grab our backs and pretend we were hurt."
Snowflakes, fingerprints and umpires' strike-three calls: No two of each are alike. That holds especially true for Hallion.
"I stretch and I'm pretty limber," said Hallion, who has 22 years of Major League umpiring experience. "Knock on wood, I've been very fortunate that nothing has happened injury-wise from doing it. If somebody else went out and tried to do it, they might pull something."
In the fraternity of big league umpires, the strike-three gesture is the individual's calling card, the one opportunity for the man in the mask to exhibit some personality and emotion. During one's ascension to the Majors, an umpire must conform to the instruction of the supervisors and execute a basic, rudimentary motion to signify a called third strike. Young umpires are taught to simply raise their right hand and then motion forward, as if they are pounding a wall with their right fist.
"That's part of umpiring school, for everybody to call things the same," Scott said. "It helps them evaluate students when they're doing the same thing. Once you get to the Minor Leagues, you're given a bit more of a license to show a little more personality. You get more leeway once you get to Triple-A and the big leagues."
When they are ultimately granted admission into the big league brotherhood, umpires often study the movements of their crew mates. From those observations, they derive their own style.
"Everybody comes up with whatever they do by observing other guys, picking out certain things one guy does and then trying to transform that into their own style," said Scott, who follows a method of stepping back, turning and delivering a jab to the gut of an imaginary adversary. "My style is certainly taken from guys I've seen over the years and then molded together to try to be something that's more personalized to me."
Dan Iassogna settled on a straightforward style 10 years ago and hasn't altered it. He pulls straight back, rotates to his right and punches the air.
"You say, 'OK, I want to have something that is unique to me that looks good on my body type and that is aggressive but doesn't show up the player,'" Iassogna said. "You want to look confident and do something that is fundamentally sound."
Iassogna, who called his first World Series in October, offers a pretty conventional display.
Fieldin Culbreth, on the other hand, curls his body to his right, then raises his left leg high in the air as if he's presenting his case to be recognized as college football's top performer.
"I love his," Barrett said. "We call it 'The Heisman.' He kicks his leg up and it's almost like he's posing for the Heisman Trophy shot."
Barksdale, who applauds his crew mate Culbreth for his innovation, sticks to a more traditional style.
"There's no way I could do that," Barksdale said. "I would probably trip or kick the catcher."
Bob Davidson, who has served as an umpire since 1982, reaches wide with his right hand to indicate a third strike before pumping both of his fists in the opposite direction. He has also fostered a reputation for imitating his colleagues' calls. Davidson restricts most of his mocking to the umpires' dressing room before games, though he admitted he has copied his cohorts on the field.
"In a lopsided game, I'll mimic their strike calls and watch them laugh a little bit," Davidson said. "I think the best strike-three in the game is Culbreth. I try to do his, but he does it a lot better than I do."
Davidson isn't the only culprit guilty of mimicry. Players and coaches take notice of the umpires' motions.
"I've looked over to the dugout and seen someone mocking my style before," Scott said. "They notice and appreciate that."
Casey Blake was one of the first victims to feel the wrath of Hallion's strike-three twist of fate, and he didn't take too kindly to the gesture.
"[Blake] said to me, 'It might have been a good pitch, but you don't have to show me up like that,'" said Hallion, who later cleared the air by telling the veteran that he meant nothing personal with his motion.
A strike-three call is the last thing a batter wants to see, no matter the degree of flair or originality. So when Scott received approval from a player he had just punched out, he knew he had found his signature call.
"'I love your strike-three call,'" the player told Scott. "'Just not on me.'"