Just for a moment it appeared Gordon Brown had been invaded by some mind-controlling alien species and was about to announce he was ready to join the euro.
Struggling for control over the euro
In a speech which had his backbenchers on the edges of their seats, he was so overwhelmingly positive about the single currency - and the benefits that would accrue to Britain from membership - that all the certainties of the past leak-strewn weeks started to fly out of the window.
Where was prudence, where was caution and where was Mr "no" to it all?
But then reality crashed back in as the real chancellor regained control of the body to conclude that - splendid though the euro was - Britain was not ready to join.
Only one of his famous five tests had been met, he said.
He would be taking tough action to help Britain meet the other four some time in the future - even changing the way inflation is calculated.
But, he hinted, that would be a very, very long way in the future.
Then the body snatcher regained control and, in what looked like a huge concession to Tony Blair, said he would revisit this entire process all over again next year.
He even declared that there could still be a referendum before the next general election and he would be publishing a bill to make that possible.
Howard seized on the divisions
You could almost see the internal battle as the two competing entities struggled for control of the chancellor's body.
And shadow Chancellor Michael Howard, in a barnstorming performance, certainly spotted the schizophrenia.
"Blair goes one way, Brown goes another way and bang goes the third way," he declared.
The entire announcement had been the result of frantic efforts by the two men to cover up their divisions, he said.
In the sort of performance his leader can only dream of, he tore into the government's indecision and ridiculed its lack of leadership.
The Tories relished every second of his wisecracking, stand-up routine.
It was abundantly clear what the past two weeks' of cabinet involvement had been all about - saving Tony Blair's face.
Numerous pairs of Tory eyes flashed between Mr Howard and Iain Duncan Smith - and it was not hard to read the minds behind them.
But when the spectacle was all over there were just two certainties left hanging in the Commons chamber.
First - the real chancellor had triumphed and Britain is not joining the euro now or, almost certainly, this side of the next general election.
Any lingering suspicions that there really will be another go next year were quickly laid to rest by his spin doctors.
Second - it was abundantly clear what the past two weeks' of cabinet involvement had been all about - saving Tony Blair's face.
Set the pace
According to former minister Peter Mandelson, the prime minister has been well and truly stitched up by his chancellor over the euro.
By leaving the crunch economic calculations in Mr Brown's hands, the prime minister had allowed him to set the pace and the policy.
When he woke up to that fact, he moved to grab back some ground by using his cabinet majority to force the chancellor to dress up his "no" verdict in positive language.
That is not to say it was not a significant concession.
The prime minister was determined that the door to euro entry before the next election should not be shut. And it wasn't.
But this was a concession the chancellor will lose little sleep over.
After all, he still has the reins of the five economic tests firmly in his fists and only an earthquake - or a seismic cabinet reshuffle - will change that.