I solemnly swear that I am up to no good.
Everyone knows that Fred and George Weasley are two of the most legendary pranksters to have ever enrolled at Hogwarts School of Witchcraft and Wizardry. Their penchant for causing strife perhaps outmatches that of Messrs. Moony, Wormtail, Padfoot, and Prongs; the original trouble-making gang of wizard teens.
While the 8-part movie series was both magical and terrifying, intense and joyful, the films provide only a window into the world that is Harry Potter. Countless details, characterizations, and handfuls of chapters just could not make the final cut into the movies. And, while Fred and George were hilarious in the films, their full ability to sow mischief and greet all situations with a healthy dose of humor truly shines in the 4,224 pages that make up this timeless story.
Quirrel and the Snowballs
Professor Quirrel, the Defense Against the Dark Arts teacher in Harry Potter and the Sorceror's Stone, had the minor drawback of Lord Voldemort's face, attached to the back of his own head. He covered up his connection to the Dark Side with an excessive stammer and a massive turban, which gave off a distinct scent of garlic. As such, the poor, twisted Quirrel was subjected to his fair share of teasing and abuse, and in that, the Weasley Twins reign supreme. In Harry's first year, they bewitched several snowballs to follow Professor Quirrel around, bouncing continuously off the back of his turban. This gets funnier the more you think about it - Lord Voldemort, the most evil sorcerer of all time, got smacked in the face with snowballs, all thanks to Fred and George.
The Toilet Seat
As the Hogwarts Express is pulling away for the first time, Mrs. Weasley gets very stern with the twins, telling them to stay well out of trouble, something they ignore. In this, she tells them that they had better not blow up any toilets, something they had not yet done. Nonetheless, it, of course, gives them an idea. After fighting to get to the Sorceror's Stone and fending off Professor Quirrel/Lord Voldemort, Harry wakes up in the hospital wing, with a mountain of sweets and treats surrounding his bed. It is then that he finds out, from none other than Albus Dumbledore himself, that Fred and George had tried to send him a toilet seat. It's a minor prank but still succeeds in showing the personality of the fun-loving twins.
A Firework and a Salamander
Dr. Filibuster's Fabulous Wet-Start, No-Heat Fireworks made several appearances throughout the Harry Potter series. But, one of their best moments never made it to the big screen. In Harry's second year at Hogwarts, Fred and George fed one of these fireworks to a salamander, and watched as the lizard swelled and grew, and eventually rising into the air, shooting fireworks out of its mouth.
Cheering Ginny Up
"The Chamber of Secrets has been opened. Enemies of the heir...Beware." Ginny Weasley picked a poor time to start at Hogwarts. Her initial excitement was quickly dampened when the memory of Tom Riddle began possessing her, forcing her to open the Chamber and set the Monster within upon the students. To try and revitalize her spirits, Fred and George took turns covering themselves in fur and/or boils, and jumping out at her, thinking that if they made light of the situation, so would she. It didn't work, but it was a good try.
Beetle Soup
At the very beginning of The Prisoner of Azkaban, the Weasley's won a 700-Galleon lottery, which funded their summer-trip to Egypt. While there, Ron picked up a pocket Sneakoscope for Harry, though, when he handed it over, he did say that "Bill says it's rubbish, because it kept lighting up at dinner." Unfortunately for Bill, the Sneakoscope worked fine - Fred and George had put beetles in his soup - they were the untrustworthy ones.
The Ton Tongue Toffee
The Weasley twins are perhaps best-known for the invention of the Skiving Snack boxes: sweets that make you ill to get out of class. One of the earliest candies they made was the Ton Tongue Toffee - a little, innocent-looking, rainbow-colored sweet. After hearing all about Dudley's cruelty and laughable size, Fred and Goerge took an opportunity to test out the toffee on Harry's bullying cousin, when the Weasley's went to No. 4, Privet Drive, to take Harry to the Quidditch World Cup. They accidentally dropped a pocketful of the sweets, picked them up, and traveled by Floo Powder back to the Burrow. But they left a single toffee behind, a toffee that Dudley ate immediately. His tongue was four feet long before Uncle Vernon and Aunt Petunia let Mr. Weasley shrink it. Revenge is sweet Ickle Dudleykins, revenge is sweet.
Canary Longbottom
The Canary Creams, another Skiving invention, didn't get the attention they deserved in the films. An innocent-looking custard, they turn the unfortunate consumer into a canary. Fred and George had left a bunch of these creams out in the common room, and they promised Neville that the creams on the table had not been bewitched. But, either by accidental chance or malicious intent, the twins were wrong, and Neville transformed into a canary, something everyone was quickly laughing about.
The Vanishing Cabinet
In the Order of the Phoenix, when the hated Dolores Umbridge took tyrannical control of their beloved school, Fred and George had a ton of ways of fighting back, and most of their battle was ignored by the movies. Umbridge built the Inquisitorial Squad, made up of Slytherins, to help cement her control over the school. Graham Montague, a Slytherin chaser and member of the Inquisitorial Squad, was in the process of taking points from Fred and George when they shoved him into a nearby vanishing cabinet. Montague was able to apparate out after a day, but wound up stuck in a fourth-floor toilet, and was in a state of disorientation for weeks afterward. Probably one of their darker pranks, this one nonetheless felt good; it was a hindrance to Umbridge's reign.
The Swamp
Fred and George, after being banned from Quidditch, decided that their future lay outside the magical walls of Hogwarts School. Once they came to that conclusion, all bets were off the table, and the twins became the bane of Umbridge's existence. When Harry decided that he needed to speak to his Godfather, Sirius Black, Fred, and George took advantage of their friend's need and decided this was a good opportunity to go all out. They set off a portable swamp in the corridor near Umbridge's office, a swamp that she was unable to remove. This was one of the twins' best bits of magic, and, as it made Umbridge's life even more difficult, it remains one of their best moments.
Peeves
While the twins themselves were the utter masters of mischief, their legacy inspired a world of terror for Umbridge. After being caught for the hallway-swamp, with Umbridge bearing down upon them, Fred and George summoned their brooms and flew away, never to return to complete their magical education. But, before they left, they turned to Peeves the Poltergeist, a character that unfortunately never made the movies, and said: "Give her hell from us, Peeves." After that, Peeves rampaged across the school like never before, throwing bags of tarantulas, juggling torches, and unscrewing chandeliers. He went so far as to chase Umbridge from the school, beating her with a cane the whole way, when she finally left Hogwarts. Other students pitched in as well; Lee Jordan let nifflers into Umbridge's office and the sheer quantity of dung bombs that were released necessitated the widespread use of the Bubble Head Charm, to breathe clean air when in the hallways. None of this would have happened if not for the mischievously inspirational legacy of Fred and George Weasley.
Mischief Managed!