10 Hilarious Doctor Who Mistakes You Definitely Didn't Notice
7. Semi-Invisible Ood (The Waters Of Mars)
This one is absolutely bizarre.
The Waters of Mars ends with the Tenth Doctor saving the doomed crew members of Bowie Base One, taking time into his own hands. Returning to Earth and realising he's gone too far, the Doctor has a bit of a meltdown, which is accompanied by a vision of his old pal Ood Sigma. Sigma soon fades away and the Doctor leaves, heading towards his date with the four knocks.
The mistake can be seen when Sigma disappears. Obviously, in real life, he didn't actually fade away like a ghost - the actor simply exited stage right, and the camera carried on taping. And how do we know this? Because, for a few brief frames, you can actually see the actor walking out of the shot.
Keep your eyes on the left-hand side of the screen when Sigma disappears (3:50 in the clip below). The snow makes it difficult to spot, but he's definitely there, and it's pretty damn funny when you do manage to notice him.