And yet, for all its import, in the three decades since that magical Tuesday night in South Philadelphia, the wonder ball has never reappeared.
There are 1980 World Series balls for sale on eBay, with prices ranging from a few dollars to a few hundred. There are plenty that were signed later by McGraw and his teammates, many at a reunion in 2000. But, as far as anyone knows, none is the actual
ball that clinched the 97-year-old franchise's first World Series triumph.
Now, 30 years later, when passion for anything Phillies-related is at an all-time high, it seems doubtful the ball will ever be found or, if it is, authenticated.
So where might it be?
The trail dead-ends quickly, during the postgame chaos. Catcher Bob Boone handed it to McGraw as a fitting keepsake for the colorful closer, who had finished so many heart-stopping contests that October. It was an act of kindness Boone instantly regretted.
"How stupid of me," Boone said recently. "Knowing Tug, he probably gave it to some little kid."
Did he? Or is it stashed among the possessions McGraw, who died of brain cancer at 59 in 2004, left scattered about with children, ex-wives, and others? Is it on a shelf in the den of some middle-aged Philadelphian who never knew its origins? Do the Phillies unknowingly have it stored away with other dusty relics from their long history?
And if someone does claim to have the ball, can he or she prove it? Was it signed? Dated? Inscribed in any way with its significance?
No one - not the Phillies, not memorabilia experts, not McGraw's relatives nor his 1980 teammates, several of whom are here this weekend for a card show at the Valley Forge Convention Center - seems to know.
And with each passing year, the chances of its ever being discovered grow more remote.
Other historic and valuable baseballs have vanished. According to Miracle Ball, a 2009 book on the subject, the Holy Grail of baseball memorabilia, the ball Bobby Thomson hit for his legendary 1951 home run, most likely was discarded in an Arizona landfill.
As Boone suggested, McGraw, whose heart was as big as his smile, might have given the clinching ball away. He could have stuck it in his locker and, after consuming considerable victory champagne and beer, forgotten about it. It could be the ball he used to play catch with his son Mark. Or perhaps it's mixed up with the other memorabilia he kept in the several residences he occupied the rest of his life.
Maybe it was inadvertently tossed out when the basement flooded in the house he owned on Perot Street, not far from the Art Museum. It might have been among the items he stored in a garage there, then gave away after he moved.
Or McGraw, whose later years were, by his own admission, "a roller-coaster heading downhill," simply could have lost the precious relic.
"If Boone gave it to Tug, I can almost guarantee you it probably never even made it out of the locker room," said Diane McGraw, the pitcher's second wife, who shared the Perot Street home with him in the late 1980s and early '90s. "Tug lost everything. I mean, he even lost two World Series rings."
This much is clear: Boone had it first.
With one out, the bases loaded, and the Phils ahead, 4-1, in Game 6's ninth inning, Frank White, the Royals' batter before Wilson, lofted a foul ball up the first-base line.
In one final homage to the franchise's cursed past, the ball bounced out of Boone's glove. But Pete Rose, signed before the 1979 season for just this kind of moment, shot his glove out like a snake's tongue and snared it.
Rose spiked the ball, then lobbed it back to McGraw as Wilson walked to the plate. The Royals outfielder, who already had fanned 11 times in the Series, swung and missed at McGraw's first pitch, then fouled the second off his foot.
An unidentified Phillies batboy - not current GM Ruben Amaro Jr., who performed that duty for the '80 club - collected the foul. But home-plate umpire Nick Bremigan threw the Phils reliever a new ball.
McGraw slapped it into his glove a few times as he stared in at Boone, then fired a fastball that was supposed to be up and in but instead sailed to a dangerous spot, high and down the middle. Wilson watched it for a ball. The count was 1-2.
Boone returned it to the pitcher and signaled for another fastball on the inner half of the plate. This time McGraw put it there, and Wilson, possibly looking for the pitcher's signature screwball, flailed and missed.
The Vet erupted with a roar so intensely high-pitched that police dogs and horses guarding the field reared. The Phillies' sore-kneed catcher stood up and triumphantly raised both arms.
Video of that last out and its aftermath reveals that the ball was still in Boone's upraised mitt as he strode calmly toward the celebration's nexus, the exultant scene surrounding McGraw on the mound.
Boone remembered that sometime later, either in that joyful scrum or back in the crowded, champagne-sodden Phils clubhouse, he handed the ball to the free-spirited reliever.
Howard Eskin, who as a young radio reporter was in the clubhouse that night as the victorious Phillies entered and who is a devoted memorabilia collector himself, said he had no idea what became of the ball.
"There was a lot going on in there," said Eskin. "It was hard to tell who was doing what. . . . And if David Hunt [whose Hunt Auctions is among the nation's largest sellers of historic baseballs] doesn't know where it is, then probably no one does."
It's not unusual for a sports artifact to suddenly surface after decades in someone's attic. Earlier this month, for example, a Minnesota family put up for auction Babe Ruth's 702d home-run ball. They had owned the autographed ball since 1934.
Such items can fetch far more than expected, especially when they have the sentimental and historic connections the McGraw/Wilson ball possesses. That Ruth ball sold for $264,500, more than three times its anticipated value.
Ruth's signature, of course, is, well, the Babe Ruth of sports autographs. The market for the '80 Phillies ball wouldn't be as hot. But to the right collector, its worth could easily be six figures.
Any collector, though, would want the ball's origin rigorously investigated. When a basketball purportedly used by Wilt Chamberlain to score his record 100th point in 1962 was about to be auctioned, doubts about its authenticity arose. Its value plummeted.
Part of the problem for anyone claiming to have the baseball is that 1980 preceded the sports-memorabilia boom. There were no holograms to identify specific Series balls, as is the case today. No team employees were designated to handle potentially historic bats, balls, and bases.
It would look like any of the hundreds of other balls manufactured by Rawlings and used in that Series, imprinted with Kuhn's signature, the red-lettered words World Series 1980, and the familiar MLB logo.
Unless McGraw, or whoever got it from him, had the foresight to note its significance in some telling way, its provenance could be impossible to verify.
"I know that Dad got the ball because Boonie told me," Mark McGraw said. "He was worried because he knew Dad could be kind of irresponsible about those kind of things.
"I do remember a ball from the '80 Series because it had that red writing [the Series designation] on it. But that was one my dad and me used to play catch with outside of our house in Media. It was just one of the balls we kept in a bucket."
McGraw, 38, an actor in California, said his father gave him another '80 Series ball, one signed by all the Phillies except his dad.
"When I asked him why he didn't sign it, he said, 'I'm your dad. You already knew I was on that team.' "
Like most major-leaguers, McGraw had accumulated a lot of memorabilia by the time he retired in 1984. But unlike many of his colleagues, he wasn't particularly interested in it.
Much of it evaporated as a result of his two divorces and many bad financial decisions. At one point, as McGraw noted in his 2004 autobiography, Ya Gotta Believe!, he was homeless and jobless, living in a Philadelphia-area discount hotel.
His first wife, Phyllis, who is remarried and living in Hawaii, kept some of his items after their divorce, but her son, Mark, said he doubted the ball was among them.
Mark's sister, Cari Lynn, who lives in Oregon, also has things, as does another child, the country music star Tim McGraw, whom the pitcher fathered out of wedlock. Tim McGraw, Mark said, has a few boxes of his father's memorabilia at his home near Nashville. He couldn't be reached for this story.
When McGraw and his second wife moved into the house at 2318 Perot St. in 1988, he kept some baseball items in the living room, the basement, and the garage.
"But I never recall seeing that ball," said Diane McGraw.
Mark McGraw said it could have been among the items his father tossed out after heavy rains flooded the Perot Street basement. But Diane McGraw said she was sure there was no ball among those damaged items.
And after McGraw moved to California in the 1990s, he gave some things stored in the Perot Street garage to the home's new owners.
"I don't think it would have been" among the things stored in the garage and given away, Diane McGraw said. "He kept the few things he considered valuable in the house. But if it was given away, and those people still have it, that would be a terrible thing."
After being contacted for this story, Mark McGraw said, he reviewed the list of items parceled out in his father's estate.
"There was no 1980 ball listed," he said.
A Phillies spokesman said that there wasn't much interest in game-used memorabilia 30 years ago, and that he wasn't sure what became of the historic ball.
As far as Hunt knows, it's never turned up at any auction.
"I've never heard of its whereabouts," said Hunt. "But you're right, that would be a really cool item."
Contact staff writer Frank Fitzpatrick at 215-854-5086 or email@example.com.