Did you record undertaker's clip about his 15 wins?
If yes then maybe you'll be able to answer that question:
“What's that mouth we barely see just before undertaker's creepy face?”
The clip last around 2 minutes.
At 1 minutes 50, pause the footage and advance slowly, step by step.
Don't go fast or you'll miss it.
Between two scenes, suddenly a (woman?) face appears.
We can only see her mouth.
Right after that, undertaker appears (great make-up!).
But what was that just before?
You don't believe me? Look!
I don't know what's more scary,
The undertaker or the undertaker mixed with that pic…