Severus Snape might have been a master of Occlumency, but his own mind was so impenetrable to us readers it can be hard to sift the heroic from the horrible.
Snape telling Harry to be quiet at the Tallest Tower

Okay, so (spoiler alert) by the end of the adventure we knew that the Potions master and short-term Hogwarts headmaster was in many ways a goodie. But frankly, the myriad contradictions in his character mean we’re still not sure about the surly professor who had everyone, including Voldemort, fooled.

He may have appeared sneering and unable to shift a grudge from a generation previous, but he protected Harry without consideration for himself.

There was one useful source from which it’s possible to derive insight into the bravest man Harry ever knew: Snape’s old copy of Advanced Potion-Making by Libatius Borage. As Harry discovered in his sixth year, it contained barely a page on which additional notes hadn’t been made.

The text included self-devised hexes and jinxes of Snape’s own invention and was at times quite revealing about the younger Snape’s attitude and personality.

Add a clockwise stir

Harry ended up with the second-hand Advanced Potion-Making copy after rejoining Potions last minute in his N.E.W.T. year.

Ever the maverick, it was during his first lesson when Harry decided to follow a set of handwritten instructions rather than the actual text. While brewing a batch of Draught of Living Death, he produced a potion so perfect it infuriated Hermione. His secret? He added a clockwise stir and crushed his Sopophorous Bean with the flat side of a silver dagger. This simple note revealed Snape’s willingness to move in a different direction to those around him to achieve the same, or better, result.


Add a sprig of peppermint

The Half-Blood Prince’s version of An Elixir to Induce Euphoria included the unorthodox addition of a sprig of peppermint that, according to Slughorn, ‘would tend to counterbalance the occasional side-effects of excessive singing and nose-tweaking’ – not behaviours you can imagine Snape wishing to encourage. Especially as the latter would draw further attention to his rather sizeable nose.

Just shove a bezoar down their throats

The words ‘Just shove a bezoar down their throats’ revealed Snape’s no-nonsense attitude. Why bother brewing something elaborate (especially when someone is foaming at the mouth beside you) when a stone taken from the stomach of a goat would protect against most poisons? This quick thinking certainly helped Ron when he drank spiked wine in Professor Slughorn’s office. Yet another example of Snape covertly saving the day.

Ron in the Hospital Wing from the Half-Blood Prince.


One of Snape’s many self-invented hexes was Langlock, which glues your victim’s tongue to the roof of their mouth, leaving them unable to speak. Considering Snape’s rather solemn disposition, this one, literally, goes without saying.


This spell fills the ears of anyone nearby with an unidentifiable buzzing, allowing you to talk freely without being overheard. The often covert Harry, Ron and Hermione would go on to use this spell a lot. But for us, the invention of Muffliato was the perfect illustration of how intense Snape’s life as a double-agent for Dumbledore and Voldemort truly was.


Hmm, now where have we seen wizards using a spell that suspends people upside-down from their ankles before? Oh yes, at the Quidditch World Cup when those Death Eaters tormented a group of Muggles. As Hermione pointed out to Harry after he tried Levicorpus out on an unsuspecting (and soundly asleep) Ron, this spell revealed the Half-Blood Prince’s dark side. If only they knew...

‘Because it’s probably not Ministry of Magic-approved,’ said Hermione. ‘And also,’ she added, as Harry and Ron rolled their eyes, ‘because I’m starting to think this Prince character was a bit dodgy.’
Both Harry and Ron shouted her down at once.
‘It was a laugh!’ said Ron, up-ending a ketchup bottle over his sausages. ‘Just a laugh, Hermione, that’s all!’
‘Dangling people upside-down by the ankle?’ said Hermione. ‘Who puts their time and energy into making up spells like that?’
Harry Potter and the Half-Blood Prince


But as Harry went on to say, you don’t get many Death Eaters boasting of their half-blood status. Or many who are in love with a Muggle-born, for that matter. Snape’s elaborate title for himself reflects his conflicted stance on the question of wizarding ancestry and the pure-bloodedness so beloved by Voldemort. He always seemed half-way between good and something darker.

PMARCHIVE-WB F8 Severus and Lily standing in Hogwarts corridor HPDH2-08081 zcNygnmVOYSgIzCBuqUzu-b23


Dumbledore put off appointing Snape as Defence Against the Dark Arts professor, not because of a lack of skill, but because he was aware the Potions master was embroiled in the Dark Arts a little too much. If ever there was an example of how damaging Dark Magic can be, it is Sectumsempra: the spell that made Harry cause actual bodily harm to another person.

Harry traditionally only Stupefied and disarmed to get out of trouble, so the moment he unwittingly, but seriously, attacked Malfoy revealed that only a truly tormented person invented this spell. It seemed Snape was already amassing real enemies, even as a young boy.

‘SECTUMSEMPRA!’ bellowed Harry from the floor, waving his wand wildly.
Blood spurted from Malfoy’s face and chest as though he had been slashed with an invisible sword. He staggered backwards and collapsed on to the waterlogged floor with a great splash, his wand falling from his limp right hand.
‘No –’ gasped Harry.
Harry Potter and the Half-Blood Prince

‘I told you there was something wrong with that Prince person,’ Hermione couldn’t help but tell Harry after this incident. ‘And I was right, wasn’t I?’

Yes, she was. But what the book doesn’t reveal is quite how much its owner changed in the intervening years…

Harry Potter to Fantastic Beasts
Discover the films