Continuity mistake: Between the time the Professor is put into the trance and waking up, his mouth mouth goes from agape, and head turned to the left, to mouth closed, facing forward.
Continuity mistake: The professor is put under a trance, referred to as "zombiefied." When it first happens, the professor is looking to his left. Later on, he's looking straight ahead.
Chosen answer: It looks like a mistake to me I see it when the Professor is put into a trance, but it is not there later.
Bowling255 ★