"It doesn't have to be a Basilisk fang. It has to be something so destructive that the Horcrux can't repair itself. Basilisk venom only has one antidote, and it's incredibly rare –" — Hermione Granger regarding Basilisk venom[src]
Basilisk venom was an extremely poisonous and corrosive substance generated by the said species.[1][2]
Overview
Basilisk venom was extremely powerful, and could kill a person within a little more than a minute at best, making the person drowsy and blurry-visioned before they died.[1] This powerful venom was one of the few substances known to be capable of destroying Horcruxes, causing them fatal damage that could not be repaired.[2] It only had one known antidote: phoenix tears, which happened to be very rare, decreasing the venom's deadliness.[1][2]
The venom's potency was apparently extremely long-lasting, as Hermione Granger was able to use the venom from the fang of a Basilisk that was dead for nearly five years.[3]
Basilisk venom was one of the few poisons that was not curable by bezoars.[2]
History
"I'm going to sit here and watch you die, Harry Potter. Take your time. I'm in no hurry." — The memory of Tom Riddle awaiting Harry Potter's death from Basilisk venom in the Chamber of Secrets[src]
In 1993, Harry Potter stabbed the roof of the Basilisk's mouth with the Sword of Gryffindor and ended up getting a fang splintered into his arm. Tom Riddle described the venom as being able to kill Harry in a little more than a minute, though Fawkes's tears healed Harry's arm and cleansed the poison.[1]
After being healed, Harry took the fang and stabbed Riddle's diary, destroying that Horcrux beyond magical repair.[1] Because Harry had stabbed the Basilisk with the sword, it was imbued with Basilisk venom and was therefore able to destroy Horcruxes and poison opponents that it cut through as well.[3]
Albus Dumbledore used the Sword of Gryffindor, which had been imbued with the basilisk's venom three years prior, to destroy Marvolo Gaunt's Ring.[4]
Ron Weasley used the Sword of Gryffindor to destroy Salazar Slytherin's Locket.[5]
In 1998, during the Battle of Hogwarts, Ron and Hermione went down to the Chamber of Secrets and destroyed Helga Hufflepuff's Cup with a Basilisk fang.[3] In the same battle, Neville Longbottom used the Sword of Gryffindor to kill Nagini.[6]
Appearances
Notes and references
Harry didn't die because Voldemort used Harry's blood to resurrect himself, tak..."
This is true. As Dumbledore explains in the DH:When Harry met Voldemort in the woods in DH, there were a lot of factors floating around:1. Voldemort had used Harry's blood to come back to life. (Blood sacrifice was still there)2. Harry was a horcrux.3. Harry had made the choice to die.So what happened was that Voldemort killed his own horcrux. If you put a horcrux in a living thing and it dies, the horcrux dies but the thing's soul does not. (" If I ran you through with this [Gryffindor's] sword, Ron, your sould wouldn't be damaged at all"~Hermione, DH)
So the horcrux is dead, and Harry's soul is intact. Then, because it was Avada Kedavra, Harry went to an in between place where he could have chosen to die. This happened because, as Dumbledore said, Harry had made the choice to sacrifice himself. He had faced death. The other reason that this happened was because Lily's sacrifice was still living on: the enchantment was strong enough to bring him back.
The Hallows were a different part of the book and unrelated to Harry's almost-death in DH. His experience with the resurrection stone did prepare him for his choice to sacrifice himself, though.Every horcrux was blown apart except Harry? Why didn't he explode when he was bitten by the serpent? And why could Voldemort kill him with the killing curse?ಠ_ಠ
J.K. Rowling has addressed this multiple times, but the clearest explanation she’s given of why the basilisk bite didn’t kill the piece of soul in Harry is perhaps in this interview. She explains that he did get poisoned, but he got the antidote fairly quickly, so it wasn’t enough to remove the soul piece.
SU: So, can I ask this? This is kind of a random question, but if Harry had this Horcrux in him, sort of, would he actually have died, say, when the dragon could have killed him, or when he was falling during Quiddich, or anything? Could he actually have died?
JKR: Well, you’ve got- if his body had been irreparably destroyed. (SU: Yeah) He has to die to get rid of that piece of soul. His body has got to be irreparably damaged. So a lot of people asked, and I think I’ve answered this since, but a lot of people immediately said, having finished Hallows, (gasps) “But then, that means in Chamber of Secrets, when he was pierced by the basilisk…” (SU: Oh, right) but no, no, no, no, he didn’t die! He didn’t die. (JN: Yeah) That was stated right in the beginning with the Horcrux, the receptacle has got to be destroyed. His body wasn’t destroyed! He got a bit poisoned, and then he got the antidote, immediately. So that’s not going to drive out this piece of soul. Sorry if I sound frustrated, but occasionally…
- PotterCast (Dec 23, 2007)
We know the soul piece was killed by a Killing Curse, which neither killed Harry or irreparably destroyed his body - but he was actually “killed” somewhat. The basilisk venom hardly had a chance to do anything, which this interview explains pretty clearly.
J.K. Rowling isn't an author to publish a mega-popular series of books and then disappear into a giant Scrooge McDuck pile of money while her fans obsess over unanswered questions and magical mysteries. Between Twitter and her Harry Potter website, the author continues to interact with fans and answer questions about the beloved magical series, some more hard-hitting than others. Harry Potter book spoilers ahead!
What happened to the three-headed dog in Harry Potter and the Sorcerer's Stone? Why didn't the Basilisk destroy the Harry-hosted Horcrux? And why on Earth did the Muggle-loathing Black family settle down in a Muggle community? These are the three questions J.K. Rowling answered for fans this week on Twitter. Let's take a look at how J.K. Rowling answered them, because they've actually left us with more questions...
Why isn't the Horcrux in Harry destroyed when Harry is bitten by the Basilisk in Chamber of Secrets?
Destroy the host, destroy the Horcrux, right? Eh, it's a bit more complicated than that...
At the end of Harry Potter and the Chamber of Secrets, Harry faces off with the Basilisk, which manages to sink one of its giant fangs into Harry before it dies. We know for a fact that Basilisk venom is one of the few substances strong enough to destroy a Horcrux. Not only does it destroy the one in Tom Riddle's diary, but Ron and Hermione also use one of the fangs to destroy Helga Hufflepuff's cup. So why wasn't the Horcrux residing in Harry's head destroyed when he was bitten by the Basilisk?
Rowling's answer is simple enough. Harry wasn't destroyed by the Basilisk or its venom. He came very close, but Fawkes' tears healed him, and apparently that helped preserve the Horcrux.
But wait, what about the resurrection stone in the ring? The stone still worked, but the Horcrux was destroyed. Someone actually managed to get that question in before Rowling had to jet...
I feel like this answer might've needed more characters than Twitter allowed, but Rowling seems to have managed to answer it as a two-parter nonetheless. Technically, the stone was cracked irreparably, so that ensures the Horcrux is destroyed. But Dumbledore's super powerful and magically precise, so he'd be able to destroy the pesky Horcrux without rendering the stone useless. If that's not enough -- pure speculation here -- maybe the fact that the stone came from Death itself, adds a bit more durability to its magical properties. That the stone could even be made into a Horcrux in the first place is a bit perplexing, seeing as it was already brimming with intense magical powers. But I'm sure there's an added argument there about Voldemort's own level of power and precision.
But I'm going to throw a followup question out there anyway. Was Harry destroyed irreparably at the end of Deathly Hallows? Because he did die, but he recovered, so I mean, define "irreparably."
There are other questions answered, unrelated to Horcruxes, so let's move on...
Why is the Black family home in a Muggle community?
The Black family isn't exactly known for favoring Muggles. Why is this pure-blood magical family living right in the middle of a Muggle community? Apparently, because they liked the house...
It does seem a bit out of character for a family as intolerant as the Blacks to reside in such close proximity to Muggles. But it's not out of character that they would use (presumed) magical means to take what they wanted from Muggles.
My followup question: What ever happened to Grimmauld Place? The last we saw of it, Harry, Ron and Hermione were fleeing the residence, which had just been exposed to the Death Eaters. Did Harry ever go back there? Is anyone living there now? It'd be great of Rowling provided an update on the Black House at some point (perhaps when Deathly Hallows finally unlocks at Pottermore?)
Moving on to the last question....
What ever happened to Fluffy?
In case you were wondering what ever happened to the three-headed dog that was used to guard the philosopher's stone in the first book...
So, Fluffy went back to Greece, and isn't lurking somewhere in the dark forest. That's comforting to know. But now I'm wondering how a three-headed dog is transported from the U.K. to Greece undetected.
Alas, that's all J.K. Rowling Tweeted for now, so I'll just have to add my curiosity about Fluffy's trip from Hogwarts to Greece to my list of questions related to witch/wizard transportation.
As for J.K. Rowling, she has some interesting things on the horizon, including the anticipated Harry Potter-related feature adaptation of Fantastic Beasts and Where to Find Them, and the small screen adaptation of her novel A Casual Vacancy.