When you come to think of it, Expelliarmus is a simple little spell; it just disarms your opponent, and gives you quite an advantage. However, there is something deeper and more reliable about the spell, and this fact is simply hard to deny when it has been tested in the world of Harry Potter, and also Doctor Who.
Expelliarmus is the spell that saved Harry from the very grips of Lord Voldemort. It’s a very ordinary spell, nothing fancy like say Sectumsempra, which mind you creates wide and deadly gashes in your victim leading him to bleed to death. However, it comes handy at the weirdest of times, and not only at Hogwarts School of Witchcraft and Wizardry, or some grim graveyard located in the Muggle world, but also in the year 1599, in the time when Shakespeare was most prominent and his works were played at the Globe Theater.
Yes, as it so happens, Doctor Who along with Martha Jones travel back to 1599, and they are right in the midst of witnessing the greatest wordsmith of all time. However, things are not all right, as a pack of wicked witches are plotting on using Shakespeare and his power over words to forward their cause. As usual, the Doctor comes to rescue, and the witches are at the verge of getting a dose of their own medicine, only, this time along with a good dose of the spell Expelliarmus. Yes, that is the spell that sealed the deal and saved mankind from extinction.
Well, if the spell can hold back the darkest of wizards, then what chance do a pack of daft witches stand, right?