If a boggart appeared to someone as a basilisk, would direct contact with its eyes kill that person?
We have to speculate, but I'd lean towards saying yes.
When Lupin was teaching Harry how to combat the effects of the Dementors and perform the Patronus charm, they used a Boggart that would then assume the form of a Dementor. In those situations Harry suffered exactly the same effects that he did when encountering a real Dementor: the cold feeling of despair, hearing his parents murder, and passing out. The cure for those effects was also the same (eating chocolate) and Harry was, eventually, able to conjure a Patronus to drive the Boggart Dementor away.
That suggests that when a Boggart assumes the form of a magical creature it behaves identically to the real thing, including any associated powers (the ability to suck away happiness in the case of a Dementor, or the death stare in the case of a Basilisk) and its weaknesses (e.g. a Patronus).
I would say no.
We have two canon instances of a boggart taking the form of a deadly creature.
The first is a banshee, which materialises as Seamus’s fear in the first class with the boggart.
Where the mummy had been was a woman with floorlength black hair and a skeletal, green-tinged face – a banshee. She opened her mouth wide and an unearthly sound filled the room, a long, wailing shriek that made the hair on Harry's head stand on end – Riddikulus! – shouted Seamus.
— Prisoner of Azkaban, chapter 7, The Boggart in the Wardrobe
In traditional mythology, the banshee’s scream usually precedes an imminent death, or is itself fatal. (I don’t believe the canon precisely defines banshees in the Harry Potter universe.) Since none of the class get so much as a nosebleed, I think that the boggart in banshee-form doesn't have the ability to actually kill people.
Later, Lupin brings a boggart for Harry to practice the Patronus charm, and at the start of the lesson he remarks:
It's the nearest we'll get to a real Dementor.
— Prisoner of Azkaban, chapter 12, The Patronus
This sounds like a boggart in Dementor form isn’t as dangerous as a fully-fledged Dementor. Indeed, he notes earlier that they can’t use a real Dementor:
I'll have to think carefully about how we're going to do this… We can't bring a real Dementor into the castle to practice on…"
— Prisoner of Azkaban, chapter 12, The Patronus
If a boggart in Dementor form is as dangerous as a true Dementor, then I think it would be disallowed on the same grounds. So we can safely conclude that a boggart cannot be as dangerous as a full-blown Dementor.
As well as these two examples, I’d argue that if it could transform into truly dangerous creatures, then it would never be allowed to leave the wardrobe, and instead be killed in situ. The risk of something like a manticore, lethifold or Lord Voldemort materialising in a third-year classroom is simply too great, even for Hogwarts.
The stare of a boggart transformed into a Basilisk might do some damage, like petrification or a bad headache, but I don’t think it could kill you.
No. I would think if it were capable of replicating the effects of a basilisk to the point of killing someone, it would not be allowed in classroom full of hormonally out of control teenagers with overactive imaginations.
There would be certain too much risk involved with that. Emotional interactions, fear, despair, okay those things might have a short term effect on a student, but no worse than their next interactions at lunchtime!
If they were that powerful, the Ministry of Magic would either be weaponizing them or disposing of them, they would never find their way into a classroom in either case.
I would definentaly say NO, it would not be deadly.
I agree with former answers based on facts from wiki. According to Lupin, the boggart form of a dementor is not fatally dangerous as the real dementor would be. As previously said by Rps the moon that formed itself before Lupin did not change the gravity of the classroom and the Banshees shriek was not harmful, which means that while Boggarts may take the form of the viewers greatest fears, they do not in fact become them. Whether this is true physically or not I am not certain, but the look of the boggart basilisk would neither kill nor petrify, or else (as previously stated) the Banshees shriek would have atleast caused a nosebleed. Whether this is true to all boggarts or just the one used for the lecture, I leave up to you.
But then comes the interesting issue of whether the basilisk would be able to kill with its fangs, poison or no poison. Can a boggart physically effect you? Can, for example, the basilisk bite you and leave a fatal wound? Can the spider crawl on you? Would Snape be able to slap you or cast a spell?
If so there is no logic as for how the moon would be able to take form as it physically would effect the athmosphere, if the boggarts magic isn't to weak to make it any bigger than the size shown in the films. Which would explain that theory.
But if not, if the boggart is more of a picture, a shadow or hologram of a kind, as you cannot touch it but it is there, then there would be no reason for Lupin to jump in front of Harry in case Voldemort took form. The argument that he would be concerned for the mental health of the students is invalid, as he is forcing them to face their greatest fears (if it's not for Harrys sake of course, he is rather partial to Harry).
If the boggarts magic was to weak to harm like a real dementor, change the athmosphere in the classroom like a moon appearing out of nowhere would or make Lupin change into a werewolf then and there, I do not see any reason for Lupin to be scared of the boggart taking the form of Voldemort. Logic would say it's magic would be to weak for its Voldemort-form to cast any fatal spells. As the Banshee couldn't harm with its voice, the magic of the boggart would be to weak for its Basilisk-form harm the viewer with its eyes.
Personally I belive that the boggart is more of a shadow picture and would only be able to harm emotionally and mentally. As itself is mostly effected by emotions.
I don't believe it would - I think they would be petrified instead.
When Harry was practicing the patronus charm he comments that it's
one nasty dementor
To which Lupin tells him that was that it was only a boggart.
The real thing would be much much worse
From this we can assume a boggart's representation of a creature's power is a lower level. So perhaps the Boggart-Snape could cast spells but they wouldn't be nearly as powerful. Lupin didn't transform when he saw the moon (although who's to say he didn't feel a little wolfy?)
Let's think about what happens when a basilisk's gaze doesn't quite work. We have examples of this.
- What happens when someone sees the reflection of it's eyes?
- What happens when it's seen in a mirror?
- What happens when it's seen through a ghost?
- What about a camera lense?
I believe if you looked straight at a boggart which was in a basalisk for you wouldn't die, but you'd be petrified instead.