Polyjuice Potion

Polyjuice Potion is a potion that allows the drinker to assume the form of someone else. It's a complicated and challenging potion that even adult witches and wizards struggle to brew correctly. The potion is incredibly advanced and has two separate parts that contain steps for each part, when brewing is complete the potion has to stew for a month before usage.

Overview
While it can account for both age and gender, Polyjuice Potion cannot be used for a human to take an animal form, nor can it be used on non-humans or half-humans.

Noticeably, the Polyjuice Potion was used many times in the events leading up to, and during, the Second Wizarding War (and possibly the First Wizarding War, although there are no documented instances of it). The potion also played a crucial role in Harry Potter, Hermione Granger, and Ron Weasley in their second and fourth year. It was also used in Draco Malfoy's plot to smuggle Death Eaters into Hogwarts School of Witchcraft and Wizardry in 1997, in the Battle of the Seven Potters, and in Harry, Ron and Hermione's Infiltration of the Ministry of Magic and their break-in of Gringotts Wizarding Bank in 1998.

Polyjuice Potion is among the products sold by the Apothecarium of Horace E. F. Slughorn.

Preparation
Independent of its actual brewing process, the Polyjuice Potion requires a good deal of preparation prior to making it. For example, the lacewing flies must be stewed for twenty-one days prior to making the potion, and only fluxweed picked at the full moon is acceptable. The total process takes approximately one month to complete.

Part 1, step one

 * 1) Add 3 measures of fluxweed to the cauldron (must have been picked on a full moon).
 * 2) Add 2 bundles of knotgrass to the cauldron.
 * 3) Stir 4 times, clockwise.
 * 4) Wave your wand then let potion brew for 80 minutes (for a Pewter Cauldron. A Brass Cauldron will only require 68, and a copper one only 60.)

Part 1, step two

 * 1) Add 4 leeches to the cauldron.
 * 2) Add 2 scoops of lacewing flies to the mortar, crush to a fine paste, then add 2 measures of the crushed lacewings to the cauldron.
 * 3) Heat for 30 seconds on a low heat.
 * 4) Wave your wand to complete this stage of the potion.

Part 2, step one

 * 1) Add 3 measures of boomslang skin to the cauldron.
 * 2) Add 1 measure of bicorn horn to the mortar, crush to a fine powder, then add one measure of the crushed horn to the cauldron.
 * 3) Heat for 20 seconds at a high temperature.
 * 4) Wave your wand then let potion brew for 24 hours (for a Pewter Cauldron. A Brass Cauldron will only require 1224 minutes, and a copper one only 18 hours.)

Part 2, step two

 * 1) Add 1 additional scoop of lacewings to the cauldron.
 * 2) Stir 3 times, counter-clockwise.
 * 3) Split potion into multiple doses, if desired, then add the pieces of the person you wish to become.
 * 4) Wave your wand to complete the potion.

Appearance
A piece of the person who is to be imitated - usually hair, but toenail clippings, dandruff, or worse can be used - is needed for the transformation; apparently, the person must be alive when the piece is taken, as Barty Crouch Jr kept Alastor Moody alive to continue harvesting his hair.

Before this final ingredient is added, Polyjuice looks like thick, dark mud that bubbles slowly. When the piece of the person to be imitated is added, however, the potion changes colour; it seems to react according to the nature of the person to be imitated, once even described as the 'essence' of the person. Good-hearted people result in more attractive colours and tastes, while mean people cause the opposite effect. Harry Potter's was a pure golden colour, whereas Gregory Goyle's tasted like "overcooked cabbage" and "looked like bogies", Bellatrix Lestrange's tasted "disgusting, worse than Gurdyroots" and Mafalda Hopkirk's was a pleasant heliotrope colour. It is likely that the taste differs from potion to potion.

Effects
The effects of a single dose last anywhere from ten minutes to twelve hours, depending on how well the potion has been brewed.[5]Continued drinking prior to the transformation wearing off extends the form's duration until the next dosage is required.[6] The complicity of the potion is such that the one Hermione brewed in her second year only lasted one hour per dosage.[2] The effects can be removed prematurely by certain magical defences, such as the Thief's Downfall.[4]

If a person dies while under Polyjuice Potion, as Mrs Crouch did, then they will retain the form of whoever they have transformed into, rather than reverting back to their original shape (although it may be possible that the effects of the potion has not worn off at the time of her death and burial, as she was careful in taking it to the end, and Barty Snr could not retrieve his wife's body in fear of exposing the jailbreak, possibly meaning her body reverted after her burial).[6]

Polyjuice can be used by a person to transform into someone of the other sex. It appears to adapt to account for the age of the person being turned into, as well as any injuries they have acquired, as Barty Crouch, Jr needed a magical eye and wooden leg when he used the potion to turn into Alastor Moody. In addition, congenital conditions of the person will apparently be replicated, as Hermione Granger required spectacles to see clearly after turning into Harry Potter.

The potion is complicated and can go awry. For example, when Hermione brewed Polyjuice in her second year, she intended to take the form of Millicent Bulstrode, but she mistook a cat's hair for Millicent's. The resulting potion caused Hermione to partially transform into a cat. As the Polyjuice Potion cannot be used to successfully transform into an animal, Hermione's change did not reverse after an hour. She went to the hospital wing and did not recover until after the winter holidays.

Likewise, the potion cannot be used by a human individual to turn into a non-human or half-breed, as Remus Lupin informed the half-giant Rubeus Hagrid.

Known uses
In their second year, Harry Potter, Ron Weasley, and Hermione Granger came to suspect that Draco Malfoy was the Heir of Slytherin. To investigate this, Hermione suggested the use of Polyjuice Potion to enable them to take on the form of Slytherin students and question Malfoy. Masterminding the effort, Hermione obtained the advanced potion's recipe (by getting Professor Lockhart to sign a note authorising her to borrow the book Moste Potente Potions from the library's Restricted Section), pilfered two of the rarer ingredients from Snape's cupboards, and undertook the complex and lengthy brewing of the base Polyjuice Potion.

She also directed how the trio were to acquire the final ingredients - hair from their targets - as well as clothing to complete the disguise. Ultimately, however, though Harry and Ron successfully assumed the appearances of Goyle and Crabbe respectively, Hermione's own attempt to take on the guise of Millicent Bulstrode went awry when Hermione used a cat hair that she had mistaken for Millicent's hair from a hair brush.

When Barty Crouch Jr was sent to Azkaban for life by his father, his mother requested that her husband allow her to switch places to save their son. The switch was made with Mrs Crouch and Barty Jr each taking a dose of Polyjuice Potion with each other's hair. Mrs Crouch was careful in drinking her remainder of the potion, until she died, so she could keep the prisoners fooled by maintaining her false appearance.

Between September of 1994 and June of 1995, Barty Crouch Jr used Polyjuice Potion to take on the appearance of Alastor "Mad-Eye" Moody, Hogwarts' new Defence Against the Dark Arts professor, in order to enter Harry Potter into the Triwizard Tournament as part of Lord Voldemort's plot to return to power. Throughout the year, Crouch stole the potion's ingredients from Severus Snape's cupboards, leading Snape to suspect that Harry himself was behind the theft; he drank the potion periodically from Alastor Moody's hip flask, to prevent suspicions. Later that year, when Crouch cornered Harry, he forgot to take the potion in excitement (ran out in the film version), and was eventually exposed.

Plot against Dumbledore
After Horace Slughorn showed a cauldron of the Polyjuice Potion to his first N.E.W.T. Potions class, Draco Malfoy stole some, and forced Gregory Goyle and Vincent Crabbe to use it continuously throughout the 1996–1997 school year. They would stand watch outside the Room of Requirement disguised as young girls, while Malfoy repaired a Vanishing Cabinet inside, as part of his assignment to assassinate Albus Dumbledore and let Death Eaters into Hogwarts.

Battle of the Seven Potters
The Order of the Phoenix made use of Polyjuice in 1997 in order to safely remove Harry Potter from 4 Privet Drive before his seventeenth birthday. Ten people - Hermione Granger, Ron Weasley, Fleur Delacour, Fred and George Weasley, Remus Lupin, Mad-Eye Moody, Tonks, Kingsley, and Mundungus Fletcher - impersonated Harry in order to act as diversions when they were ambushed by Death Eaters despite Harry's initial protests. Soon after, Harry himself used it to disguise himself as "Barny Weasley" at Bill Weasley and Fleur Delacour's wedding.

Infiltration of the Ministry of Magic
The trio used Polyjuice that they stole from Moody to infiltrate the Ministry of Magic to search for Salazar Slytherin's Locket in September of 1997. Harry, Ron and Hermione disguised themselves as Albert Runcorn, Reginald Cattermole, and Mafalda Hopkirk, respectively.

Gringotts Break-In
The following year, Hermione used the remaining Polyjuice Potion again as part of the trio's plan to break in to Gringotts in order to retrieve Helga Hufflepuff's Cup from the Lestrange Vault. Using a strand of Bellatrix Lestrange's hair that had fallen on her sweater while Bellatrix interrogated her at Malfoy Manor, Hermione assumed her form. However, there wasn't enough, so Ron had to simply use cosmetic design to disguise himself. The effects of the potion were washed away by the Thief's Downfall at the bank.

The lack of suspicion in anyone in all these incidents leads one to the understanding that Polyjuice Potion is very uncommon. Granted, Severus Snape knew someone was stealing the ingredients from his cupboards and suspected Harry Potter, but that is more indicative of Snape's eagerness to blame Harry for anything than any actual guilt.

2020 Ministry theft
Albus Potter, Scorpius Malfoy, and Delphi used Polyjuice Potion to disguise themselves as Ron Weasley, Harry Potter, and Hermione Granger respectively and sneaked into the Ministry of Magic. Albus, as Ron, convinced Hermione to go elsewhere while they searched her office for a Time-Turner. Solving a series of puzzles from Hermione's bookcase, they finally discovered and stole the Time-Turner.