21 super difficult 'Harry Potter' trivia questions even die-hard fans have trouble with

• Test your knowledge of J.K. Rowling's fantasy series with our set of impossibly hard questions about the "Harry Potter" books.
• Below you'll find a question above each image, with its answer revealed below as you scroll.
• Visit Insider's homepage for more stories.

Do you consider yourself to be an expert on all things "Harry Potter"?

There are many internet hubs perfect for putting that knowledge to the test, from discussions on the /r/harrypotter to user-submitted quizzes on Goodreads. In order to track down the toughest "Harry Potter" trivia questions, we put our own memory to the test on Scholastic's "Wizard's Challenge" — an online quiz with a wide range of difficulty.

Combining expert-level questions found there along with some doozies asked during a New York City "Harry Potter" trivia night, we've compiled a list sure to challenge the average "Harry Potter" fan.

Scroll down to test your knowledge. The questions are above the photos, with each answer revealed below.

What is Fred Weasley's chosen code name on Potterwatch, the secretive radio program set up by the Order of the Phoenix?

Harry, Ron, and Hermione hear this name in "Deathly Hallows."      Warner Bros.

Answer: Rapier.

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Ginny Weasley bought a pet Pygmy Puff from her older brothers' joke shop. What did she name it?

Fred and George Weasley opened "Weasleys' Wizard Wheezes" together.      Warner Bros.

Answer: Arnold.

Voldemort stole Helga Hufflepuff's cup from an old woman named Hepzibah Smith. What was the name of her house-elf?

Dobby wasn't the only house elf featured in "Harry Potter."      Warner Bros.

Answer: Hokey.

What is the name of the Apparition instructor who comes to Hogwarts in Harry's sixth year?

Dumbledore and Harry apparate together in "Half-Blood Prince."      Warner Bros.

Answer: Wilkie Twycross.

The visitor’s entrance to the Ministry of Magic is an abandoned red telephone booth in London. What is the five-digit code you must dial to get in?

The numbers spell M-A-G-I-C on a phone's keypad.      Warner Brothers

Answer: 6-2-4-4-2.

On the wall across from the Room of Requirement, there is a tapestry showing a wizard trying to teach trolls ballet. What's his name?

The characters in "Harry Potter" passed this tapestry many times.      Warner Bros.

Answer: Barnabus the Barmy.

In the Quidditch World Cup, Ireland's team had three main chasers: Mullet, Troy, and Moran. Which one scored the first goal?

The Weasley Family all supported Ireland.      Warner Bros.

Answer: Troy.

In the Hall of Prophecy there are rows and rows of glowing orbs. Which row contains the prophecy about Harry and Voldemort?

Harry found this prophecy in "Order of the Phoenix."      Warner Bros.

Answer: Row 97.

Harry first took the Knight Bus in "The Prisoner of Azkaban." How much does a ticket cost if it includes hot chocolate?

The Knight Bus is an unusual mode of transportation.      Warner Bros.

Answer: 14 sickles.

What is the max speed for a Firebolt broomstick?

Harry is known for his talents in Quidditch.      Warner Brothers

Answer: 150 mph.

Cedric Diggory let Harry use the prefect's bathroom in "The Goblet of Fire." What man's statue is next to the special lavatory entrance?

Cedric told Harry the password as a favor.      Warner Bros.

Answer: Boris the Bewildered.

For Harry's 17th birthday, what color did Hermione turn the leaves of the Weasley’s crabapple tree?

The color was a nod to his role as seeker on the quidditch team.      Warner Bros.

Answer: Gold.

This one is a two-parter. Where does Vernon Dursley work, and what does the company produce?

The Dursley family in "Harry Potter and the Chamber of Secrets."      Warner Bros

Answer: Grunnings, a drill manufacturer.

Dumbledore has a scar above his left knee that is a perfect map of what?

He mentions this to Professor McGonagall in "The Sorcerer's Stone."      Warner Bros.

Answer: The London Underground.

In "The Sorcerer’s Stone," Harry and his friends are awarded last-minute House Points, putting Gryffindor ahead of Slytherin by just 10 points. What was the final tally?

Neville Longbottom was the last-minute hero that year.      Warner Bros. Pictures

Answer: 482 to 472.

How many possible Quidditch fouls are there?

Quidditch players are constantly at risk of injury throughout the game.      Warner Brothers

Answer: 700.

Name every ingredient contained in Polyjuice Potion. (Hint: There are seven.)

This one is a doozy.      Warner Bros.

Answer: Lacewing flies, leeches, powdered Bicorn horn, knotgrass, fluxweed, shredded Boomslang skin, and a bit of the person you want to turn into.

How many staircases does Hogwarts have?

New students need to learn the secrets of the castle.      Warner Bros

Answer: 142.

Monkshood and wolfsbane are the same plant, also known as what?

Snape grilled Harry about this on his first day in Potions.      Warner Brothers

Answer: Aconite.

Harry, Ron, and Hermione help save the Sorcerer's Stone from being stolen. How old was its co-creator, Nicholas Flamel, when he decided to destroy it?

Hermione, Harry, and Ron at the library.      Warner Bros.

Answer: 665.

Many know that Gryffindor's ghost is Nearly Headless Nick. But what is his full name?

Nearly Headless Nick at a Hogwarts feast.      Warner Bros.

Answer: Sir Nicholas de Mimsy-Porpington.