The Ghost of Frankenstein/YMMV

"Ygor:"Tonight, Ygor will die for you!""
 * Nightmare Fuel: Ygor gets his brain transplanted into the Monster, and there is never another brain switch in the series. But the Monster becomes nothing but a lumbering, inarticulate brute after this. Which means that Ygor, thanks entirely to his own treachery, ends up trapped inside of a hideous monster. Forever.
 * Moral Event Horizon: The Monster crosses this when he demands that Frankenstein put a little girl's brain into his head after kidnapping her from her home. And then he crushes poor old Ygor to death!


 * Ygor crossed the Horizon years ago, but even so, his desire to usurp his "friend's" body so he can live forever deserves dishonorable mention.