If there's anything a true Potterhead learns, it's that J.K. Rowling hid countless clues in the books and we'll probably never find them all. While we did all get the obvious ones, like the Latin translation for spells, there are some little tidbits we've been missing for about two decades.

Grab your favorite Harry Potter mug, wrap yourself in your Hogwarts House-themed blanket and get ready to educate yourself.

20 Snape's first words to Harry were about Lily

Years later, this probably was the least known Harry Potter tidbit. But it probably speaks most to the fact that J.K. Rowling literally thought of every little detail, even from the beginning of the series.

During Harry's very first Potions class, Professor Snape asks, “What would I get if I added powdered root of asphodel to an infusion of wormwood?” It seems like an unnecessarily difficult question for a first-year student. But it really wasn't a question as much of a veiled admission of his feelings for Harry's mother.

Asphodel is a type of lily. It actually means "remembered by the tomb" or "my regrets follow you to the grave." Meanwhile, wormwood is actually associated with regret or bitterness. In Harry's sixth year, Professor Slughorn brings up those same ingredients—when he makes the Potions students brew Draught of the Living Death. If you look at Snape's life after Lily died, he was existing in a sort of "living death." It's like Snape is expressing his mourning over Lily and the state of his life in one question. Those first words meant a lot more than we realized.

19 Harry and Ron predict the Triwizard Tournament tragedies

Let's face it, Potterheads: Harry and Ron weren't exactly the most engaged students. Harry probably only did as well as he did in school because he had his mother's genes (everyone's description of Lily made it sound like she was basically Hermione). It was really no surprise in Harry Potter and the Goblet of Fire when they decided to goof off instead of doing their Divination work. Somehow, they end up accurately predicting Harry's harrowing journey through the Triwizard Tournament.

Harry kicks off the predictions by forseeing that he's "in danger of burns," which we all know turned out to be true. The first task of the tournament required the challengers to work with (well, more like around) dragons. Next, Ron says Harry will lose a "treasured possession." This is right again because each of the champions had a friend or family member taken from them during one of the tasks. Then, they predict that he'll be "stabbed in the back" by someone he thought was a friend. That ends up being Professor Moody, who actually turned out to be Barty Crouch Jr., a Death Eater who kidnapped Moody and used the polyjuice potion to steal his identity.

18 Ron also guessed something about Voldemort

Maybe Ron missed his calling as someone in a more supernatural field? He seems to have a few accurate guesses under his belt, which doesn't seem like it should all be by coincidence. On top of getting those details right about Harry's Triwizard Tournament challenges, he also guessed something right about Tom Riddle, AKA Lord Voldemort.

When Ron ended up in detention, he was forced to spend that time cleaning in the trophy room. This was also after one of spells backfired, leading him to keep vomiting slugs. He kept throwing them up on a trophy awarded to none other than Tom Riddle. Since he had to clean it so many times, the name stuck in his head. When Harry finds his diary, Ron mentions how he knows that name. Wondering why he got the award, Ron muses that he may have killed Moaning Myrtle, which he jokes would've done everyone a favor. Later, we find out he was right because Tom was responsible for Myrtle's death.

17 Dumbledore's cryptic greeting

Petunia always acted like she hated magic. She spoke of it and her magically inclined sister with nothing but disdain. It was pretty crazy when we found out Petunia was not only jealous of the attention Lily got from her parents but also of her sister's magical abilities. You'll remember that Petunia wrote a letter to Professor Dumbledore, asking to be allowed into Hogwarts and to be a witch. He kindly rejected her admission request.

When they meet face-to-face in Harry Potter and the Half-Blood Prince, Dumbledore remarks, "We have corresponded, of course." Now, most of us believe that was referring to the howler he sent her previously. But correspondence requires an initial letter and then a response that. So, what he really meant was their letters about her request to come to Hogwarts. Leave it to Dumbledore to be unfazed by adding onto an already awkward situation.

16 Petunia mentions Snape in the fifth book

Obviously, Petunia spent much of her young life around the world of magic since her sister was a witch, but it was a surprise when we found out she retained some of the details. When Dudley was attacked by Dementors in Order of the Phoenix, Aunt Petunia isn't surprised by the creatures, instead showing an unexpected knowledge of what they are. When a baffled Harry asks how she so much about them, Petunia says, "I heard – that awful boy – telling her about them – years ago."

We immediately assume "that awful boy" was Harry's father, James. It's not like we'd be surprised by her insulting him, after all. But she was actually talking about Snape, which makes more sense. James is Harry's father, so she'd probably have just referred to him by his name or "your dad" if she meant him. The "boy" she mentioned was the kid Lily befriended as a child (who Petunia didn't like), AKA Severus Snape.

15 Dumbledore's sister may have been an obscurial

This isn't confirmed yet, but we have enough evidence to be 99.9% sure that it's true. Recently, Fantastic Beasts and Where to Find Them gave us a very detailed description and depiction of what an obscurial is. To refresh your memory, it's a young wizard who suppresses their magic, usually leading to the development of an obscurus; that's a dark cloud that can bring on destruction and death to anyone who angers an obscurial or just gets caught in its path.

Now, let's look at Ariana Dumbledore, the younger sister of Professor Dumbledore and his brother, Aberforth. When she was a 6 years old, Ariana was tortured so horribly by Muggle boys who saw her using magic that she was never able to safely use it again and refused to practice at all. Her father attacked the boys to get revenge and was sent to Azkaban, but never told the authorities why he did it. Aberforth remarked in the books that Ariana would've been "locked up" in St. Mungo's if anyone found out what was wrong. Why else would she be in that type of danger unless she'd started exhibiting obscurial tendencies?

Her mother moved the family to Godric's Hollow and they pretended like Ariana was ill, presumably so nobody would question why she never left the house. At 14, Ariana had an "explosion" that killed her mother. We're betting her obscurus did it in a fit of rage after some sort of disagreement. The explosions weren't unusual either. Aberforth said, "She wouldn't use magic, but she couldn't get rid of it; it turned inward and drove her mad, it exploded out of her when she couldn't control it, and at times she was strange and dangerous."

Then, we also need to consider the fact that Gellert Grindelwald was so obsessed with finding an obscurial that he took someone's identity in the Ministry of Magic to track one down. He and Albus were very close as teenagers, so it wouldn't be far-reaching to assume he told Gellert about his sister's condition. He also may have witnessed one of her explosions and saw how powerful an obscurus can be.

Before you point out that obscurials usually don't live past the age of 10, don't forget that Ariana used her magic for the first six years of her life. That may have given her more time than magical children usually get.

14 They'd already found the locket horcrux

Remember the locket horcrux? It made anyone who wore it depressed and paranoid. Poor Ron really got the worst of it, getting so wrapped up in the dark thoughts that he started suspecting his best friends and ended up leaving them for a while. Although, our heroes went through a lot to get that horcrux, they'd actually seen it before.

When Harry arrived at Grimmauld Place, AKA the home of Sirius Black's family, he and other youngsters were tasked with cleaning up while the adults actually planned for their future battles against the Death Eaters. As they tidied up the drawing room, the teens found a lot of odd stuff, including a heavy locket that they couldn't seem to open. Yep, Harry went searching around the world for what was right in front of his face. Remember, Regulus had the locket, but he couldn't figure out how to destroy it, so he pawned it off on Kreacher (who also couldn't destroy it).

13 Harry had also seen the diadem horcrux before

Seriously, Harry needs to work on his observation skills. If he actually paid attention to what was going on around him, the time it took to search for horcruxes could've been cut in half. Like we said before, his mother's genes are the only thing keeping him from being a total screw up.

When Snape suspected Harry was using his old Potions book, which was full of helpful notes, he tried to sniff it out. To avoid being punished for cheating, Harry and Ginny hid it in the Room of Requirement, so Snape would never know for sure that he had it. They put it underneath the chipped bust of a warlock and then "perched a dusty old wig and a tarnished tiara" on top of it. Of course, the tiara was the diadem. He literally held it right in his hand. Oh, Harry.

12 The vanishing cabinet's important role

The true failure of the movies is that they didn't include Peeves, one of our favorite Hogwarts ghosts. That means anyone who didn't read the books is missing out on the character and some of the things he did. In Chamber of Secrets, nearly Headless Nick wants to get Harry out of trouble with Filch, so he convinces Peeves to damage a vanishing cabinet in the room right above Filch's office.

That same vanishing cabinet takes a very important role later on. Malfoy spends an entire school year repairing it in Half-Blood Prince. The movies sort of brush over the difficulty it took for the young wizard to repair it, which isn't easy work at all. We'd be impressed if he wasn't doing it for nefarious reason (at least on the Death Eaters' end since he was mostly just doing it out of fear). Malfoy eventually does it, allowing to the Death Eaters to make their way into Hogwarts and usher in the death of Dumbledore.

11 Why Ron and Neville weren't great at magic

Ron wasn't so great at casting spells. There were worse wizards, but there were definitely better ones, too. Since he came from a long-established wizarding family, you'd think he'd be much better at it. One of the reasons he isn't Professor Flitwick's model student is because Ron doesn't have his own wand at first.

The running joke with the bullies at school (we're looking at you, Draco Malfoy) is that the Weasleys don't have a lot of money and always make do with hand-me-downs. Ron's first wand actually belonged to his older brother, Charlie. As we learn from Mr. Ollivander, the wand chooses the wizard, so there's a special connection there that helps magical abilities to grow. Ron doesn't get that because the wand isn't really his.

The same goes for Neville Longbottom, who didn't have his own at first either. His wand actually belonged to his father, who was tortured into insanity. Both of his parents were aurors, so he should have definitely started out with more magical ability. But that wand hindered his skills.

10 We always knew Snape could read minds

When you're sneaking around, it's not uncommon for you to get paranoid and believe that someone can read your mind. When you're a student at Hogwarts, it can actually be true. In the first book, Harry believes Snape is responsible for trying to steal the Socerer's Stone. (Harry literally thought any shady thing happening probably involved Snape.) He starts to worry that his Potions professor knows what he and his friends are up to because he has a horrible feeling Snape can read minds. Well, he turned out to be very right. We find out later in the series that Snape is skilled in Legilimency, which means he can enter your mind and poke around inside to see what you're thinking. We're glad our teachers never had this skill.

9 Harry isn't actually hearing his parents when the Dementors come

Harry was a baby when his parents were killed. He has no memory of them or of that night, which is obviously common for anything that happens at that age. However, every time he's near a Dementor, he hears his mother screaming in her final moments. What if that's not from his memory? Dementors are known for making people experience the worst moments of their life again. But the night Harry's mother died wasn't just the worst moment in Harry's life, it was also the worst in Voldemort's. It's the moment the Dark Lord came closest to his biggest fear—death. Harry is a horcrux, so he has part of Voldemort in him. What he's really hearing is something from Voldemort's memory, not his own.

8 Trelawney wasn't technically wrong about Harry's birthday

Professor Trelawney wasn't the hack many of her colleagues thought she was. She had a pretty great track record for predictions, including ones outside of the two prophecies she made about Lord Voldemort. During a Divination class, she tries to guess when Harry was born, saying, "Your dark hair… your mean stature… tragic losses so young in life… I think I am right in saying, my dear, that you were born in mid-winter?" Since Harry was born on July 31, everyone just assumed she was wrong. But there was a dark-haired, mean boy with tragic losses in his life who was born in mid-winter—Lord Voldemort. Because Harry is a horcrux, she's actually sensing him inside of Harry and making a prediction based on that.

7 She also predicted Dumbledore's passing

Of course, many students go home for Christmas, but the ones who don't are treated to a holiday meal at Hogwarts. Twelve students and teachers were seated at a table in the Great Hall when Professor Trelawney was invited to join, but she refuses, "If I join the table, we shall be thirteen! Nothing could be more unlucky! Never forget that when thirteen dine together, the first to rise will be the first to die!" What she doesn't know is that there are already 13 people at the table. Ron is holding Scabbers in his pocket, AKA Peter Pettigrew. Dumbledore was the first to stand up from the table and eventually becomes the first to die. File that under yet another reason Peter Pettigrew was the worst person in the Wizarding World next to Lord Voldemort.

6 The same goes for Remus Lupin

This is yet another death that we're still not over. It turns out, we could've been prepared for it. In Deathly Hallows, the Order transferred Harry from his unhappy childhood home on Privet Drive to the Burrow. When they get to the Weasleys' home, there are 13 people left after Moody is killed. (It's sad we mostly knew him when he was actually Barty Crouch using polyjuice potion.) They all gather around to raise a toast in the wacky wizard's memory. Who's the first to get up? Unfortunately, it's Remus Lupin. As we all know, he ends up dying later during the Battle of Hogwarts, along with his wife, Tonks. The saddest part is that they left behind an infant son, Teddy.

5 Harry's Sneakoscope actually does work

In Prisoner of Azkaban, Ron gives Harry a Sneakoscope for his birthday. The device is supposed to detect if anyone untrustworthy is lurking nearby. Well, the Sneakosope ends up whistling and spinning constantly. It was a cheap gift, so Harry, Ron and Hermione just assume it's not well made and must be broken. It turns out, the frugal gift is actually working just fine. We can't forget there was someone trustworthy around them all the time—Peter Pettigrew. Wormtail spent the first few years of their Hogwarts experience disguised as a rat after faking his own death to frame his Sirius for his murder. (Of course, this is because he doesn't want anyone to know he told Voldemort where Lily and James were staying so he could murder their baby.) That definitely isn't something a trustworthy person would do.

4 Neville was a true Gryffindor

Neville starts out as a very fearful young man. He's afraid of just about everything, but mostly Professor Snape. Gryffindors are marked by their bravery, but it was starting to look like he didn't have much in him until the Battle of the Department of Mysteries. Even then, it wasn't courage out of the norm for anyone in any other Hogwarts House.

Then, the Battle of Hogwarts came. When Neville was faced with the Death Eaters, he fought back and refused to join them. Because of his bravery, he was able to pull the sword of Godric Gryffindor out of the Sorting Hat. This is a big deal because it means Neville was never misplaced in Gryffindor. We learned in Chamber of Secrets that only a true Gryffindor can pull the sword out of a hat.

3 The subtle suggestion in Goblet of Fire

A lot of J.K. Rowling's references are subtle and can take us years to unpack. Then, there are the moments that she basically spelled out for us. In Goblet of Fire, gardener Frank Bryce made the fatal mistake of eavesdropping on Voldemort in the Riddle house. He hears He-Who-Must-Not-Be-Named speaking to Wormtail about a task he believes most of his followers "would give their right hands to perform." Of course, later in the book Voldemort is brought back to life after Wormtail completes the process by cutting off his on right hand. Sometimes, being a little "on the nose" with writing can still end up getting lost in translation. We're probably so used to J.K. Rowling being complicated that this was a huge surprise.

2 Mrs. Figg was brave

We're first introduced to Arabella Figg as an older neighbor who watches Harry while the Dursleys are out having fun because they're too evil to take their nephew along with them. We find out later in Order of the Phoenix that she's a witch who's been watching over Harry on Dumbledore's orders the entire time. That's not the only secret we found out about Ms. Figg. It turns out, she was a a lot more than a kindly old lady who looked after a neglected little boy. When Harry is in the hospital at the end of Goblet of Fire, Dumbledore tells Sirius: "You are to alert Remus Lupin, Arabella Figg, Mundungus Fletcher—the old crowd." Yep, Figg was also part of the Order and apparently had been back when Voldemort first rose to power, too. It makes sense that Dumbledore would chose someone formidable to protect Harry.

1 The key to get into the Ministry of Magic

You'd think that the Ministry of Magic would be an insanely protected place, but everything we find out about it seems to show off its vulnerabilities. First off, one of the ways employees get in is by flushing themselves down a toilet in a public restroom. It was easy enough for Harry, Ron and Hermione to figure out, so we can only imagine it wouldn't take a curious Muggle too long either. Another way to get into the Ministry is by using an abandoned phone booth. Once you get in, you'll just have to type a few numbers in the keypad—62442. These probably just seem random to the innocent reader at first, but it's actually another little detail placed in the text by J.K. Rowling. If you type those numbers into an old-school keypad, it'll spell "MAGIC." It's a cute addition and also another glaring issue with security at the Ministry.

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