[Harry Potter 7] Do The ... Locomotion
The Battle of Hogwarts had all sorts of great moments as (almost) everyone mobilized to battle and did their bit for victory (even if, in Professor Trelawney's case, it consisted of dropping crystal balls onto their heads). When Professor McGonagall started the shenanigans by calling the statues and armor to the defense of Hogwarts, did anyone else think that the spell consisted of the words "Treguna Mekoides Trecorum, Satis Dee"?
EDIT: Guess that disproved the Professor McGonagall is a Death Eater theory.