The Harry Potter Fan Theory That Has Fans Looking Closer At Professor Slughorn

Professor Slughorn (Jim Broadbent) could have been just another pompous professor in the vein of Gilderoy Lockhart (Kenneth Branagh) in Chamber of Secrets — but he was actually talented at the subject he was hired to teach: potion-making.

On the less positive side, Slughorn also had a propensity for buddying up with students he deemed to be the future elite. And a strong sense of morality wasn't on his list of essential traits, which explains why Neville Longbottom (Matthew Lewis) wasn't allowed to join his so-called Slug Club, but a slew of future Death Eaters and even Lord Voldemort (Ralph Fiennes) himself made the cut.

Like another former Hogwarts teacher — Professor Quirrell (Ian Hart) in Harry Potter and the Sorcerer's Stone — Slughorn was a minor character who had a major impact on some of the most pivotal events in the Wizarding World. If the potions professor hadn't explained horcruxes to a young Tom Riddle (Frank Dillane), Lord Voldemort might never have come into existence.

However, there's an even subtler Harry Potter fan theory that has fans looking closer at Professor Slughorn — and this time, he might just be on the right side of history.

We're first introduced to felix felicis in Professor Slughorn's potions class in Harry Potter and the Half-Blood Prince, where students like Romilda Vane and Katie Bell are working to create the perfect potion. As Hermione (Emma Watson) explains, its other name is liquid luck — although translated from boring old muggle language Latin, felix felicis actually means luck's luck or happy luck — J.K. Rowling isn't the only writer who loves a Latin reference. In the movie, Slughorn explains, "One sip and you will find that all of your endeavors succeed — at least until the effects wear off."

We get to see this in action when Harry (Daniel Radcliffe) uses the potion against Slughorn to find out what really happened when he discussed horcruxes with Tom Riddle. It certainly makes Harry — or, as he puts it, Felix — extremely confident, and helps him track Slughorn down. But in the end, it's a combination of two old-fashioned muggle forces — alcohol and guilt — that push Slughorn to confess. Interestingly, in the books, Harry saves some of the potion and later gives it to Hermione, Ron and Ginny. But in the movie, he glugs down the whole vial — far more than the sip Slughorn mentioned in class. It's possible to have too much of a good thing.

If you can't get enough of Harry Potter fan theories that change everything, you'll get a kick out of Reddit user EquivalentInflation's theory about Slughorn's felix felicis. Even though, as Slughorn himself notes in the movie, it's, "Desperately tricky to make, disastrous should you get it wrong," EquivalentInflation suggests that maybe Slughorn has a larger supply than he's letting on. "If he's willing to be that generous with it, he has to have a decent supply for himself, or at least the capacity to make more," the Redditor writes. And unlike the other potions Slughorn presents to the class, the felix felicis is in a small glass vial — suggesting that there is a bigger top-up supply somewhere.

The theory doesn't end there. EquivalentInflation points out that Slughorn isn't known for his courage or dueling skills, yet he not only fights in the Battle of Hogwarts, he survives. In the Deathly Hallows book, he even joins Professor McGonagall and Kingsley Shacklebolt to duel with Voldemort. Could it be that he took a little liquid luck before the battle? Even stronger evidence of this is seen in Deathly Hallows Part 2. Just before McGonagall (Maggie Smith) prepares to cast the spell to activate the statues, Slughorn can be seen running down the steps behind her, drinking from a small bottle.

However, he may have had other, more everyday uses for it too. During that first potions class in which Slughorn introduced the students to felix felicis and awarded Harry a vial, Seamus (Devon Murray) sends a Sopophorus bean flying through the air — and Slughorn catches it. Pure skills, lucky catch or... felicitous catch?