Sprinkled through Bernard Brogan's recently-published memoir The Hill are little moments of realisation that the inter-county game is beginning to move beyond the author's ageing torso, each mini epiphany knocking a dent in his own wrought-iron self-belief.
One comes in the early stages of the second half of last year's All-Ireland semi-final.
Brogan, sore at his exclusion from Dublin's match-day squad, watches the game from the floor of his home in Castleknock in the company of his infant twin sons.
At half-time, Mayo lead by two points. And then comes Dublin's powerplay, spearheaded by the man who ostensibly, has taken Brogan's place at the apex of the team's attack.
"Con O'Callaghan is just magic," Brogan writes. "A beast. Lee Keegan is as magnificent and as streetwise and as tough as any back we've ever encountered.
"Only last weekend he tied up Michael Murphy. And yet today Con just tosses him aside as if he were a rag doll and leaves him on his arse as if he were a novice skater.
"It's actually scary."
That he went on to score four points in the All-Ireland final replay, earning a nomination for Footballer of the Year, and subsequently a fourth Dublin SHC medal with Cuala, added to an already developed image of the indestructible 'King Con'.
At 23, he'd won a fourth All-Ireland senior football medal to go with his two All-Ireland club hurling titles, two All Stars and Young Footballer of the Year award.
His ability to switch between codes with such ease and at such short notice, offering the same direct potency in both, without visible signs of wear or tear, made the collection of all that silverware even more impressive.
And then, in the most innocuous possible circumstances in a warm-up before a Sigerson Cup game in mid-January, O'Callaghan popped his shoulder and missed all of Dublin's five games in the League.
And in August, after scoring 0-5 against Na Fianna in a group SHC game, he pulled up lame after aggravating a knee injury.
It forced him to miss three games across two codes for the club and suggested that O'Callaghan was, in fact, mortal after all.
And then he came back in their hurling semi-final, scored 0-3, set up a goal and thundered at the Lucan Sarsfields defence looking for all the world like he'd never been away.
"He is just a very unique person, both physically and his personality as well, just a specimen," says Brian Fenton.
"I don't know how he does it. The fella, I think, can do things that no-one else can.
"I know he was carrying a knock or something. But then I went golfing with him, and he smoked us all playing golf."
It would be tempting to say Dublin GAA has never produced anything quite like O'Callaghan in terms of versatility and prowess in both codes, were it not for one of the men he'll be facing in tomorrow's county hurling final.
And whatever O'Callaghan ultimately achieves in his chosen sports, he'll do well to match Conal Keaney for longevity.
Keaney will be 37 when he togs out in his 11th Dublin senior hurling final tomorrow, but he'll be 38 when he plays in his fifth Dublin senior football decider seven days later.
In this, the most bizarre of club seasons, he has started week on week for his club in football and hurling, excelling in both.
When they played Fenton's Raheny in the football quarter-final, Keaney, who made his inter-county debut 15 years before O'Callaghan made his, kicked five points from play.
"You are looking at man-marking jobs," Fenton explains. "And then Conal Keaney just kicks over five points. You are saying this fella's winding back the clock.
"It is just a credit to him. I don't know him personally. But yeah, he's been amazing this year.
"I caught a couple of glimpses of the Jude's-Ballyboden game and he was the same, just kicking scores for fun and being a big leader.
"More power to him. I hope I'm going that well when I'm his age.
"But the two of them," Fenton adds, "they're freakish. To be that good at both is just incredible."
Simon Lambert has watched Keaney, first as a supporter and now as a team-mate for both the Ballyboden footballers and hurlers.
"You don't see too many of him around," he notes.
"Maybe Con, who's probably 15 years his junior.
"They don't come around too often. What can you say about Conal?
"It's not that he's just starting - he's performing every week as well, from the hurling and football side. He's scoring heavily. He's involved in so much."
It's less than two years since Keaney had shoulder reconstruction surgery and came storming back to feature for Dublin, playing a key part in their stirring Leinster SHC victory over Galway in Parnell Park.
"He looks after himself off the pitch - he always has," Lambert notes. I grew up idolising him. He's a freak in terms of how he's able to still go on and perform at the highest level.
"And look, he'll probably come into a Dublin hurling set-up maybe as well now in a couple of weeks, and I've no doubt he'll perform at a high level there again."
"You don't get these lads … they might come around every ten or 15 years, Conal and the likes of Con O'Callaghan next."
Two of a very rare kind.