Much like fire, magic is a beautiful and raging thing, a power that needs to be handled with the greatest of care and treated with the utmost respect. That is the reason, after all, that wizards go to Hogwarts – to learn how to tame it. For as with fire, if you play with magic, you can get burned – or splinched, or turned into a cat, or even – when magic goes really wrong – die. Here are some of the best (and worst) examples.
Lord Voldemort accidentally turns Harry Potter into a Horcrux
Let's start at the beginning, where even Lord Voldemort, one of the most powerful wizards of all time – sees his magic go spectacularly wrong. You know the gist, of course. In pursuit of immortality, the Dark Lord has split his soul into several pieces – through murder – and bound them to objects, transforming them into Horcruxes.
As long as those Horcruxes survive, so does Voldemort. It's dark, powerful magic: so powerful that not even a wizard as gifted as Voldemort can fully command it, as he found out when he tried to murder Harry Potter as a child. As Professor Dumbledore explains in Harry Potter and the Deathly Hallows, Voldemort had rendered his soul so unstable that when he tried to kill him – and the curse rebounded – a part of himself became latched on to Harry, making him the seventh Horcrux. And if even a wizard like Voldemort can mess up, then what about wizards like…
Neville Longbottom’s entire time at Hogwarts
You know all that stuff we said about magic being a beautiful and raging thing, a power to be treated with the utmost respect? Well, magic, meet Neville Longbottom. Neville is to casting spells what Harry is to staying out of trouble, and his time at Hogwarts is littered with all sorts of magical mishaps.
There's the time he lost control of his broom and broke his wrist; the time he accidentally transplanted his ears on to a cactus; that other time when his wand slipped and vanished one of the legs of his desk; when he hurled Professor Flitwick across a room; when he prodded his Mimbulus mimbletonia and it spewed liquid that smelled like ‘rancid manure’ everywhere; and, of course, the millions of cauldrons that he melted in Professor Snape’s Potions class. Aw well, at least he made up for it in the end.
Ron Weasley makes himself vomit slugs
If the wand truly does ‘choose the wizard’, then there must have come a point during Harry Potter and the Chamber of Secrets when Ron's first wand really regretted its life choices. For it's here – during Harry and Ron's chaotic car crash into the Whomping Willow – that Ron's wand finds itself snapped in half, only to then be tied loosely back together with Spellotape.
This, as you can imagine, doesn’t go well. It accidentally injures Seamus Finnigan during Duelling Club; it conjures up clouds of rotten-egg-smelling smoke; it shoots out of Ron's hand and strikes Professor Flitwick in the head. Its most famous malfunction, though, is Ron's attempted hex of Draco Malfoy – in retaliation for him calling Hermione a ‘filthy little Mudblood’ – which backfires and causes Ron to vomit a continuous stream of slugs. Magic is weird.
Everything Gilderoy Lockhart ever did
His books may paint him as a dashing magical hero, but Gilderoy Lockhart's tenure as Defence Against the Dark Arts teacher exposed him as a charlatan, a liar and, above all, the showiest thing to happen to magic since spoon bending. This, of course, was clear to see from his very first class, where he let loose a cage of Cornish Pixies, but it quickly became obvious whenever he actually tried to perform spells.
Take, for example, his attempt to get rid of the snake during Duelling Club, when he instead sent it flying into the air; or his infamous medical skills, when his spell to heal Harry's broken arm after a Quidditch accident instead removes the bones – turning Harry's arm into limp limb of rubbery flesh. He even manages to get his only talent, Memory Charms, wrong, inadvertently wiping his own memory at the end of Harry Potter and the Chamber of Secrets. Although, in all fairness, that was down to Ron's broken wand – all hail Ron's broken wand!
Hermione turns herself into a cat
As Professor Snape once said, brewing potions is a subtle science: a delicate art where – much like clockwork – all the components must not only be exact, but work in perfect harmony with one another. As such, it's easy for potions to go wrong – and that especially goes for the Polyjuice Potion. Hermione learned this the furry way in her second year, when her attempt to take the form of Millicent Bulstrode resulted in catastrophe: she mistook a feline hair for one of Bulstrode's. The mistake caused her to transform into a cat: a big problem given that the Polyjuice Potion cannot be used for cross-species transformation, and so led to her lying in the hospital wing for weeks. Yet another reminder that if you’re going to brew Polyjuice Potion, make sure that your ingredients are purrfect.
Harry goes handsfree
Given how chaotic and volatile magic can be, wizards use wands to channel and control it, and we only really see the likes of Dumbledore and Voldemort being able to command magic without one. Young, untrained wizards, however, are not Dumbledore or Voldemort, and often find their magical abilities taking on a life of their own when they are emotional or in danger.
You see this right at the beginning of Harry Potter and the Philosopher's Stone, when Harry inadvertently vanishes the glass of a boa constrictor enclosure, setting the snake loose in the zoo. You also see it in Harry Potter and the Prisoner of Azkaban, when Aunt Marge takes her insults too far by speaking ill of Harry's parents. Enraged, Harry loses control of his magic and accidentally blows her up like a balloon.
One of the most basic rules of magic is to make sure you pronounce things right. It's Win-gar-dium Levi-o-sa, for example.
Harry learns a lesson in enunciating in Harry Potter and the Chamber of Secrets, when his first encounter with Floo Powder ends up with him landing in the wrong place. Why? Because the Floo Network requires you state your destination clearly. And instead of saying 'Diagon Alley', Harry gets some ash in his throat and fluffs the words, landing him in the dodgy Knockturn Alley. And you thought getting on the wrong bus was bad.
Ron gets splinched
Still, the Floo Network is a lot safer than teleportation magic, a.k.a. Apparition/Disapparition, which is so advanced and dangerous that wizards need a licence before they can perform it. Why? Because splinching, that's why. Splinching, according to Apparition Instructor Wilkie Twycross, happens when a wizard's mind isn't focused, meaning that while one part of you may teleport to your destination, you may end up leaving another part of your body behind.
Ron Weasley failed Twycross's class, which would come back to haunt him in Harry Potter and the Deathly Hallows – caught in a dangerous situation, he tries to Disapparate without a licence, and ends up Apparating with a huge chunk of his upper arm missing. Still, it could have been worse. Susan Bones left behind a leg in her first Apparition class, while Arthur Weasley tells a story about two wizards who tried to teleport without a licence, and Apparated with only half their bodies…
Last but certainly not least is the reminder that magic going wrong can often have tragic consequences. Take Luna Lovegood's mother, Pandora Lovegood, for example. In Harry Potter and the Order of the Phoenix, Luna reveals that her mother – an extraordinary witch who liked to experiment with magic – died when one of her new spells backfired, killing her in front of her nine-year-old daughter. One of the saddest tales is that of Ariana Dumbledore, the younger sister of Albus.
At a young age, an attack by a group of Muggle boys – who saw her performing magic – left Ariana destroyed, traumatised to the point where her magical abilities became unpredictable and uncontrollable. This would manifest itself in the worst of ways, with Ariana, at the age of 14, causing a magical explosion during a fit, killing her mother. And as if that wasn't enough, Ariana herself would go on to be inadvertently killed by a wayward spell cast by either Albus, her second brother Aberforth or Dark wizard Gellert Grindelwald during a three-way duel.