If Jos Buttler's pupils were craters, then the entire England team could have tumbled into the void of his thousand-yard stare, after one of the most evocative errors ever committed to Ashes legend.
Dropped catches are a fact of Test cricket, and an occupational hazard of wicketkeepers in particular - "you get that one chance and that's what you'll be judged on," Matt Prior, Buttler's England predecessor, said during BT Sport's close-of-play analysis.
And yet, some drops just carry more weight than others, be it the moment of the match, the magnitude of the occasion, the identity of the reprieved … or in this late, late instance, all three, as Marnus Labuschagne was horribly spilled under the floodlights, to deny James Anderson his first wicket of the Ashes, and to suck any hope that England had harboured of a late redressing of the first-day balance.
It was, by any wicketkeeper's standards, an irredeemable shocker. A regulation nick, at a comfortable height to Buttler's right, and one that he ought to have swallowed - not least given the confidence with which his day had begun, thanks to a stunning leg-side grab to dismiss Marcus Harris off Stuart Broad.
That earlier moment had been a perfectly choreographed marriage of footwork and hand-speed, as Buttler flung out his right mitt to prise England's only new-ball breakthrough. And yet, by degrees, his ebullience ebbed, most notably through a separate - less ghastly but equally culpable - spill off Labuschagne, as he misjudged the pace of a glove down the leg side and was almost through his leap before the ball reached his hands.
"He's a human being," Graham Thorpe, England's assistant coach, said at the close. "It's bit like being a goalkeeper. You can keep magnificently throughout the day, but if you drop a catch, it gets highlighted. But we'll get around him and try to be philosophical about it as well, because I think you have to be. At the end of the day, we're playing a game of cricket."
Perhaps it's too soon to pronounce Buttler's drop as the moment that the Ashes were lost. But if, as you might expect from a side that has won 10 of its last 11 home fixtures against England, Australia were to grind this latest formidable start into another imposing finish and a 2-0 series lead, then posterity is sure to replay his agonising miss, time and time again, until it is grooved into the sport's annals.
Just ask Ashley Giles, who dropped Ricky Ponting at square leg on this very ground in 2006-07 - an error which could not be held directly responsible for the horrors of England's final-day collapse, but which set in motion a chain-reaction of Australian recovery for the remainder of the match. Or how about Thorpe himself, whose reprieve of Matthew Elliott at Headingley in 1997 holds a similarly grim fascination for those of a ghoulish bent?
"Everyone who's played this game and drops a catch is always disappointed," Thorpe added. "For Jos, it's going to hurt tonight but he's going to have to get out of bed and come again, and enjoy his day tomorrow, because that's what Test cricket is all about."
And yet, it's not just Buttler who will have to come again because, by the close, England's collective morale was through the floor. The day had started with Australia's captain Pat Cummins being pinged as a Covid close contact - a drama that gave rise to momentary parallels with another fateful pre-toss incident at Edgbaston in 2005. Instead, the day ended with Cummins' deputy (and predecessor) Steven Smith ensconced in a 45-run stand with his bat-alike Labuschagne, and primed to cash in on what has already proven to be an unforgiving deck.
The moment looks likely to matter all the more, because in the absence of Mark Wood - the one man who could have bludgeoned a way through these conditions - the sameness of England's five-pronged right-arm seam attack has been exposed, exactly as happened to their four-pronged right-arm seam attack in the same contest four years ago.
And given that the first three of those bowlers - Anderson, Stuart Broad and Chris Woakes - were unchanged from that original floodlit contest, it probably shouldn't have come as a massive surprise.
"I thought we stuck at it well," Thorpe said. "I thought they played particularly well in those first few sessions, but obviously in Adelaide, it's a good toss to win. Throughout the day, the run-rate didn't go too far. But we'd have obviously loved to have more wickets down at the end of the day."
But just as Anderson had briefly ignited that 2017-18 match with a memorable spell under the lights, so the circumstances stacked up this time around, whereby England had one shot at redemption at the end of an arduous day. As ordained from the outset, twilight arrived along with the second new ball, and there was just enough nibble in the conditions to give England hope of a flurry of late breakthroughs - the sort of jackpot that could have justified their earlier focus on bowling dry, rather than striving for breakthroughs.
Then Buttler dropped his clanger, and it was as if England had set themselves a massive great mammoth trap, only to watch their big beast trot harmlessly over their meticulously prepared pit of wooden stakes, and away to graze in the neighbouring pasture.
For the onlooking Prior, however, the moment was especially culpable because he felt it had been telegraphed by Buttler's sluggish body language in the build-up to England's final push.
"Everyone thinks it's your hands that get you a catch. It's not, it's your footwork," Prior noted. "You've got to do the work with your legs, and then your hands just follow.
"There were a couple of takes down the leg-side where [Buttler] had a dive and a bit of a fall and a flop. That's lazy wicketkeeping. If he was on it in the first over the day, he would have been hop-skipping across, and would probably have stayed on his feet without diving."
It's an agonising challenge now for Buttler to regroup from here and put in the performance that can both restore his own standards, and lift the levels of the men around him. It's well known that he took some persuading to pitch in for the Ashes, amid the pressures of touring during the pandemic, but ultimately he did so because everything about his recall to the Test team, back in 2018, has been leading up to this point.
He's a proven England matchwinner, an indisputable legend of the white-ball game, and a player who only last month was belting most of Australia's Test attack all around Dubai in a contemptuous onslaught at the T20 World Cup. For a split-second in the first Test at Brisbane, he channelled that same belief and focus into a spirited 39-run counterattack. But by the second innings of that dispiriting team performance, his joie de vivre had dissipated and he was back to poking uncertainly in the channel outside off.
And now, here he is, snatching at England's most priceless chance of an Ashes lifeline, as if taken by surprise by the bounce of the new ball and the sudden effectiveness of England's greatest fast bowler in helpful evening conditions. It's a dichotomy that encapsulates the wider failings of the team of which he is a central personality. And if a player of such proven stature as Buttler can't raise his game for the clutch moment of the Ashes, what hope the wider team?