Britain's Got Talent viewers were amazed and "shaken" by one act's performance on the show this weekend, as others quickly predicted it was a familiar face in disguise.
But some viewers weren't all that impressed, and even some of those who were believed they'd cracked the case.
Judge Amanda Holden took centre stage as she was hypnotised by an 'invisible' person, who wreaked havoc across the stage.
One jumpy moment saw the balloon she was made to hold randomly burst, before Amanda managed to work out what co-judge Alesha Dixon had in her hands.
Amanda was asked to pick an item out of the "lost property box" too, which she hid under a cloth as requested.
At the iconic London Palladium, The Phantom made Alesha choose an item out of the same box, a dummy, which Amanda soon guessed correctly as it was apparently the first thing that came to her head.
Amanda had been asked to place a piece of chalk on a board at one point too, and The Phantom then wrote out the word 'keys' on the board, seemingly without any assistance.
It wasn't until she lifted the cloth after this that she revealed to everyone she had taken some keys out of the box at the start - but the act soon took a turn.
David Walliams recognised the keys in Amanda's hands to be his own, with a video on the screen appearing to show an invisible person entering his dressing room, and stealing the keys from the table.
The judges and viewers were completely baffled by the whole act and how it was achieved, but some eagle-eyed viewers believe they have worked it all out.
Some fans believe the chalk was magnetically connected to the board and that this was how the word was written out - while as for the box of items, viewers think Amanda would have seen the dummy in there when picking the keys.
One viewer tweeted: "Chalk is a magnet," as another said: "Would have been more believable if the chalk left the board between letters."
A third viewer commented: "If we see it back it looks like keys were written on the board before the phantom did it," as another fan suggested: "that was clearly staged with pre-recorded audience reactions because the writing on the chalk board was definitely vfx."
Others noticed the chalk appeared to move from the place Amanda left it, with one tweet reading: "Are we just ignoring that the chalk started in the middle of the board and then was suddenly top left?"
Another fan commented: "What a load of rubbish the chalk moved from the centre to the side of the board without making a mark. And no way did she pull a big set of keys out."
Meanwhile, other viewers were more concerned about the fact someone was able to steal David's keys, without him even noticing they were gone.
One comment said: "Bit of a security issue if someone took Davids keys from his dressing room."
Got any theories or thoughts on the audition? Let us know in the comments section below
Britain's Got Talent airs Saturday at 8pm on ITV and ITV Hub.
