The Tooth Fairy - Ralph Fiennes
Before he was Voldemort, Ralph Fiennes was The Tooth Fairy. Red Dragon is the prequel to Silence of the Lambs. Fiennes' transformation included fake tattoos all over his body, which had to be reapplied each day of shooting.
Pazuzu - Eileen Dietz
The crew for The Exorcist called up Eileen Dietz to see if she could take on the role of the devil, Pazuzu. Although she wasn't actually the King of Hell, they superimposed her face onto the devil's to create a super eerie, nonhuman face. This moment, along with many others from the film, has stayed with people their entire lives.