Harry Potter and the Philosopher's Stone first hit cinemas (and changed our lives 5eva) 16 years ago, so it's safe to say HP fans will have seen it roughly a gazillion times and know it through and through.
But while you may have memorised every Malfoy zinger and every know-it-all Hermione rant, there's a certain spell that you've been mishearing all these years.
Remember that scene when Seamus Finnigan was trying to turn his water into rum?
The spell most people were probz hearing was:
"Eye of rabbit, haffring hum, turn this water into rum."
But the witches and wizards at Seventeen.com have discovered that this isn't the spell, at all.
The spell is actually: "Eye of rabbit, harp string hum, turn this water into rum."