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"It was a horrible sight. Twelve feet tall, its skin was a dull, granite grey, its great lumpy body like a boulder with its small bald head perched on top like a coconut. It had short legs thick as tree trunks with flat, horny feet. The smell coming from it was incredible. It was holding a huge wooden club, which dragged along the floor because its arms were so long."
Harry Potter and Ronald Weasley witnessing the troll for their first time on Hallowe'en[src]

The Troll in the Bathroom was a mountain troll[1] brought into Hogwarts School of Witchcraft and Wizardry on 31 October (Hallowe'en) 1991 by Quirinus Quirrell, then possessed by Lord Voldemort, in an attempt to steal the Philosopher's Stone of Nicolas Flamel.[2]

Quirinus Quirrell was able to control this troll, a rare talent. He said later that he had a gift with trolls.[2] He also used another troll to help protect the Philosopher's Stone.[3]



Hermione: "You're saying it wrong. It's Wing-gar-dium Levi-o-sa, make the gar nice and long."
Ron: "You do it, then, if you're so clever"
— Hermione and Ron arguing during Charms class[src]
PS Wingardium Leviosa feather

Hermione Granger mastering Wingardium Leviosa

On 31 October (Hallowe'en) 1991, the first-year Charms class were taught how to perform the Levitation Charm (Wingardium Leviosa) by Professor Filius Flitwick. All the students in the class struggled with its pronunciation, apart from Hermione Granger, who lectured Ron Weasley on his incorrect casting and cast it perfectly herself, much to Flitwick's delight.[1]

After class, a particularly annoyed Ron Weasley insulted Hermione to his friend Harry Potter by remarking that she was a "nightmare" who had no friends due to her bossy and boastful nature. Hermione overheard this, and was later seen crying in the girls' bathroom by Parvati Patil, while Neville Longbottom reported this to an unknowing Harry and Ron.[1]

The Hallowe'en feast[]

"Troll -- in the dungeons -- thought you ought to know."
— Quirrell distracting Hogwarts school[src]
Troll in the Dungeons!

Quirrell "warning" Hogwarts about the troll

As the students were attending the Hallowe'en Feast, Professor Quirrell suddenly sprinted into the Great Hall frantically with a terrified expression over to the teacher's table, warning Albus Dumbledore of a troll that had been let into the dungeons before collapsing on the floor.[1]

The whole student body then began to panic in an uproar, with Headmaster Dumbledore having to first silence them all with Purple Firecrackers before telling the Prefects to take the students back to their dormitories and for all teachers to follow him to the dungeon to deal with the loose troll. During the walk back to the Gryffindor common room, Harry Potter remembered Hermione was unaware of this, and he and Ron subsequently went to rescue Hermione.[1]

Attack in the girls' bathroom[]

"Hermione had sunk to the floor in fright; Ron pulled out his own wand -- not knowing what he was going to do he heard himself cry the first spell that came into his head: "Wingardium Leviosa!" The club flew suddenly out of the troll's hand, rose high, high up into the air, turned slowly over -- and dropped, with a sickening crack, onto its owner's head. The troll swayed on the spot and then fell flat on its face, with a thud that made the whole room tremble."
— Ron having defeated the troll with the Levitation Charm[src]
Troll knocked out PSF

Ron and Harry after having defeated a fully grown Mountain troll

Harry and Ron ran toward the bathroom and spotted Severus Snape, following Quirrell to the third floor corridor. They then noticed the troll lurking about the corridor and unknowingly locked the troll in the girls bathroom with Hermione. Realising their mistake, they ran in to rescue a terrified Hermione. Ron threw a metal pipe at it, which, along with all the shouting, aggravated it. Harry, meanwhile, jumped on the troll and accidentally shoved his wand up its nose. This caused the troll to howl in pain and it began to swing its club. With Harry's life in danger, Ron ingeniously thought of the first spell that came to his head, the Levitation Charm, which he had learnt earlier that day, and cast it to levitate the troll's club. He then dropped the club on top of its head, knocking it out instantly and causing it to fall to the ground incapacitated.[1]


"Well, I still say you were lucky, but not many first-years could have taken on a full-grown mountain troll. You each win Gryffindor five points. Professor Dumbledore will be informed of this. You may go."
— McGonagall rewarding Ron and Harry for having defeated the troll[src]
Professors ps

The Professors witnessing the aftermath

After the troll fell the floor, Harry observed that it was only knocked out, not dead. Harry extracted his wand from the troll's nostril, with it being covered in troll bogeys, much to his disgust. Then, Professors Minerva McGonagall, Severus Snape and Quirinus Quirrell entered the bathroom to witness the aftermath of the pandemonium. A horrified McGonagall questioned the boys as to what they were doing going after a fully grown mountain troll, but Hermione lied to McGonagall, claiming she had sought the troll out herself. McGonagall then lectured the three first-years on their recklessness, deducted five points from Gryffindor from Hermione for being foolish, gave Ron and Harry five each for having defeated the troll, and sent them away to the Gryffindor common room. Afterwards, Harry, Ron and Hermione became best friends, forming the "trio".[1]

Harry: "You let the troll in?"
Quirrell: "Certainly. I have a special gift with trolls, -- you must have seen what I did to the one in the chamber back there? Unfortunately, while everyone else was running around looking for it, Snape, who already suspected me, went straight to the third floor to head me off -- and not only did my troll fail to beat you to death, that three-headed dog didn't even manage to bite Snape's leg off properly"
— Quirrell revealing his deception to Harry Potter in the Underground Chambers[src]

Harry, Ron, and Hermione originally assumed that Snape was behind the "troll business", but Harry, trying to stop Voldemort in his attempt to steal the Philosopher's Stone, found out that it was Quirrell, not Snape, who had let the troll in.[2]

With the Hogwarts faculty desiring to quickly move the troll off of the school grounds before it could cause any further damage, Dumbledore contacted Alastor Moody for assistance. Given both the danger of the mission and the need for discretion, as one of the students involved in defeating the troll was the famous Harry Potter, Moody had the request elevated to the purview of the Rare, Obscure, and Confounding Case Division. At the suggestion of Callum McClintock, Crescent Flump assigned Jacob's sibling the mission to remove the troll from the girls' bathroom without being seen. Flump had intended to send a senior ROCC agent to complete the task, which was outside of Jacob's sibling's purview of cursed objects, but, knowing that Jacob's sibling was a recent graduate of Hogwarts and could thus blend in more easily, Flump informed them of the basic details of their mission before sending them to meet with Dumbledore at Hogwarts.[4]

In their guise as an employee of the Magical Maintenance Department, Jacob's sibling arrived at Hogwarts and met with Professors Dumbledore, McGonagall, Snape, and Quirrell, with Dumbledore explaining that Quirrell had discovered the troll in the Hogwarts dungeons and that Harry Potter, Ron Weasley, and Hermione Granger were the students who had bravely, albeit recklessly, incapacitated it. Jacob's sibling quickly accepted that a Weasley was involved in the event, having gotten into mischief with Bill and Charlie Weasley while they were at Hogwarts, but Snape seemed suspicious of why Moody would have sent a janitor to remove the troll. After convincing a begrudging Snape that they had the necessary skills to remove the troll, Jacob's sibling and the Professors planned out how to remove the troll from the bathroom unseen, with Jacob's sibling noticing both Snape's injured leg and Snape seeming to glare at Quirrell in the process. Jacob's sibling suggested the use of a spell similar to Mobiliarbus to move the troll, with Dumbledore informing them of the existence of the spell Mobilicorpus, which could be used to easily lift and transport the troll. As Jacob's sibling hadn't been taught the spell, Dumbledore arranged for Professor Flitwick to meet them in the girls' bathroom to teach them how to use Mobilicorpus.[4]

Jacob's sibling met with Flitwick in the girls' bathroom, being astounded by the amount of damage the troll had done to the room. Flitwick expressed his opinion that either Harry, Ron, or Hermione were either extremely skilled or extremely lucky to have defeated a troll in their first year before helping teach Jacob's sibling Mobilicorpus, warning them that miscasting the charm could wake the troll. After an extensive practice session, Jacob's sibling was able to cast the charm successfully, levitating the troll slightly off the ground. Flitwick readied to inform Dumbledore to keep the hallways clear while Jacob's sibling moved the troll, reminding them that they had to determine a safe location to which to move it. Given that it was a mountain troll, Jacob's sibling intended to move it back to the mountains by cutting through the low-traffic Forbidden Forest.[4]

Jacob's sibling transported the troll to the Forest Grove, although they accidentally nearly directed it straight into a tree while leaving Hogwarts. In the forest, they ran into Callum, who explained that Flump had sent him to ensure that Jacob's sibling had "finished the job". Callum offered his support on the mission, but claimed that he intended to tell Flump that Jacob's sibling had handled the mission all by themselves when they returned. However, the troll soon woke up and broke free of the Mobilicorpus charm. Enraged at having been levitated, the troll brandished its club at Jacob's sibling and Callum, forcing Jacob's sibling to duel it. After hitting the troll with multiple spells, including the Knockback Jinx and the Bombardment Spell, the beast eventually grew tired and retreated back towards the mountains, where Callum asserted that it would remain safe without harming anyone any further. Callum informed Jacob's sibling that he was the one who had suggested them for the mission and that he would report back that Jacob's sibling had handled their task admirably, believing that Flump would respond well to their good result.[4]

Jacob's sibling returned to Hogwarts to report the completion of their mission to Headmaster Dumbledore. Dumbledore explained that the troll's attack was just the latest of a series of strange happenings that had been occurring at the school since Harry Potter arrived, with Dumbledore having to take extra precautions when it came to the safety of both the students and a certain item. Although Dumbledore refused to tell Jacob's sibling what the item was, he indicated that he might need their help again in the near future, with Dumbledore hinting that he was aware of Jacob's sibling's status as an undercover ROCC agent.[4]

Behind the scenes[]

Screenshot 931

The troll as depicted in the console versions of the Philosopher's Stone video game

Troll in the Bathroom 2 LEGOY1

The troll as depicted in LEGO Harry Potter: Years 1-4


The troll as a LEGO minifigure

  • In the PS1 and PC versions of the Philosopher's Stone video game, when dealing with the troll, Harry must cast the Knockback Jinx to destroy pieces of debris the troll throws at him, while Ron charms the club with the Levitation Charm. In the console versions, the troll must be defeated the Softening Charm, by having the troll hit enchanted Spongify tiles, which will cause its club to bounce back and strike it head, which must be done five times to knock it out. There is also a major plot difference in the game, where they rescue Hermione from the second-floor girls bathroom when it should be the first floor.


Notes and references[]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Harry Potter and the Philosopher's Stone, Chapter 10 (Hallowe'en)
  2. 2.0 2.1 2.2 2.3 Harry Potter and the Philosopher's Stone, Chapter 17 (The Man with Two Faces)
  3. Harry Potter and the Philosopher's Stone, Chapter 16 (Through the Trapdoor)
  4. 4.0 4.1 4.2 4.3 4.4 Harry Potter: Hogwarts Mystery, Beyond Hogwarts, Volume 1,