Since first concocting the germ of an idea for what would become the Harry Potter series in 1990, Rowling has sold more than half a billion copies of her work globally, making her one of the most successful authors in recent history. Despite Rowling’s work attracting a fair amount of controversy and criticism (largely stemming from the author’s recent hardline stances on trans issues and her gross oversimplification of complex social issues in her work), the series has nonetheless ballooned into a behemoth franchise sprawling into amusement parks, video games, films, stage productions, and increasingly rabid fan circles.

J.K. Rowling first wrote the names of the Hogwarts houses on a barf bag.

Rowling revealed in a 2017 tweet that she’d first written the names for the famed Hogwarts houses (Hufflepuff, Ravenclaw, Slytherin, and Gryffindor) on a barf bag provided to her on a flight.

The myriad of names for the universe’s magical flora come from a real book of botany.

In a 2003 interview with 60 Minutes, Rowling revealed that she’d taken inspiration for the naming of various fictional plants from a real book; Culpeper’s Complete Herbal, a botany compendium written by 17th-century herbalist and physician Nicolas Culpeper.

Rowling considered killing off a member of the franchise’s beloved trio.

In a 2013 interview with the actor behind Harry Potter himself, Daniel Radcliffe, the author admitted she’d once seriously considered killing off Potter’s right-hand man and best friend, Ron Weasley. Rowling also disclosed she’d also toyed with the idea of Hogwarts’s beloved gamekeeper, Hagrid, meeting a grim demise.

Even Stephen King was afraid of Dolores Umbridge.

While reviewing the series 5th installment, Harry Potter and the Order of the Phoenix, the de facto king of horror lit stated, “The gently smiling Dolores Umbridge, with her girlish voice, toad like face, and clutchy, stubby fingers is the greatest make-believe villain to come along since Hannibal Lector.”

Harry’s eyes aren’t green in the films for a very specific reason.

Throughout the duration of the series, Harry’s lichen green eyes he’d inherited from his mother are a notable, oft-remarked-upon feature in the books. However, Radcliffe’s eyes in the film appear a steely blue, his natural color. The production originally attempted to fit Radcliffe with colored contact lenses but, following an allergic reaction from Radcliffe, they scrapped the idea and just matched Radcliffe’s natural eye color to the actor they’d later cast as his mother.

Peeves was originally meant to be in the films.

The role of Peeves, Hogwarts’s resident poltergeist prankster, was originally intended to be taken on by British comedian Rik Mayall. Mayall even completed filming scenes for the first movie, only to later learn director Chris Columbus had cut them on account of his dissatisfaction with the spector’s on-screen appearance.

The actor portraying Moaning Myrtle was much older than her character.

Despite her impeccable portrayal of the ghost of a sordid 14-year-old girl, Shirley Henderson, the actor cast to play Myrtle, was 36 at the time of filming The Chamber of Secrets.

Makeup artists applied Harry’s iconic lightning bolt scar thousands of times.

Throughout the course of filming the franchise’s 8 installments, makeup artists emblazoned Radcliffe and his stunt doubles with Harry’s iconic lightning bolt scar more than 5,000 times.

Michael Jackson wanted to compose a Harry Potter musical.

Rowling told Oprah Winfrey in 2010 that the King of Pop had once approached her with a proposal to adapt the Harry Potter books into a musical. Though Rowling would decline Jackson’s proposal, the Potterworld would eventually make it to the stage in 2016 with the stage production Harry Potter and the Cursed Child.

Rupert Grint has never seen any of his iconic giant spider scenes.

Early in the series, Ron was predominantly known for his red hair, bumbling remarks, and crippling arachnophobia. Actor Ruper Grint, much like his character, also harbors a deep fear of the leggy creatures, going so far as to entirely avoid watching any of his scenes featuring the film’s gargantuan, anthropomorphic spiders.

Jason Isaacs almost passed on playing Lucius Malfoy.

Isaacs originally auditioned for the role of Gilderoy Lockhart, the deluded, narcissistic Defense Against the Dark Arts instructor in Prisoner of Azkaban, only to be later offered the role of the cold and calculating Malfoy patriarch. Isaacs originally intended to decline the role over concerns the villainous Lucius was too similar to his previous role as Captain Hook, the primary antagonist in 2003’s Peter Pan.

Russian lawmakers were furious about the film’s depiction of Dobby.

While rumors have never been officially corroborated, the physical appearance of Dobby the House Elf is alleged to be based on Russia’s totalitarian president, Vladimir Putin. Putin’s cronies were enraged to the point they began to plan lawsuits against Warner Brothers Studios for the perceived sleight.

Eddie Redmayne auditioned to play Tom Riddle.

Though Redmayne would later take on the role of famed magizoologist Newt Scamander in the Fantastic Beasts films, the English actor revealed in 2016 he’d originally auditioned for the role of Tom Riddle but failed to get a callback.

Hagrid was the first role cast.

Even before the titular role of Potter was decided, late actor Robbie Coltrane was cast as Hogwarts’s resident gamekeeper Rubeus Hagrid before any other roles were settled on.

Harry’s scar appears slightly different in the books.

Though Harry’s lightning bolt-shaped scar appears to hover just above his right brow throughout the films, on the book’s original covers it appears settled right in the middle of his forehead.

Hermione almost had buck teeth in the movies.

Early in the book series, Hermione’s prominent front teeth are consistently made a point of ridicule and mockery by her crueler fellow classmates. Production attempted to fit Watson with prosthetic teeth but scrapped the idea after finding Watson began having difficulty speaking with them on.

Fred and George Weasley share a suitable birthday.

The Weasley twins, noted for their proclivity for pranks and japes, were born on April 1st (i.e. April Fool’s Day).

Rowling herself is a Hufflepuff.

Though it is oft derided as the most milquetoast of the 4 great Hogwarts Houses, Rowling has stated she herself would have been sorted into Hufflepuff were she to attend the wizarding school.

The driver and conductor of the Knight Bus are named for Rowling’s grandfathers.

Stan Shunpike and Ernie Prang, the conductor and driver of the Knight Bus respectively, take their first names from Rowling’s own real-life grandfathers.