Harry Potter and the Chamber of Secrets - Wait... He's a Ghost
Nearly Headless Nick was petrified right? But he's a ghost so how can he possibly drink the potion to heal him? He should still be petrified at the end of the movie.
For that matter, how is a living human supposed to drink a potion if s/he is petrified?
Obviously, the answer must be that the de-petrification potion is applied by some means other than the victim drinking it (e.g. by being used as an ointment). This is NOT a goof.