Harry reveals himself and uses the Cruciatus Curse on Amycus after Amycus spits in McGonagall's face, and then she uses the Imperius Curse to subdue him so that Harry can continue on his mission to find the Horcrux without alerting anyone else.
Allowing the caster to completely control another's actions, the Imperius Curse is one of the three Unforgivable Curses and has been outlawed for its use as a Dark Art. It is possible to resist the Imperius Curse but doing so requires exceptional strength of mind.
Why did Professor Moody repeatedly put the imperius curse on Harry?
Professor Moody was determined that he would get his wish granted from Harry. This is the reason that he continued with his curse by the time Harry did not agree to perform the Reflector Spell and return it to him.
Mcgonagall shoots fire at Snape from a nearby torch. Snape then transfigures the fire into a snake, which Mcgonagall blasts into smoke, followed by summoning a swarm of daggers.
So, had Snape gone all out in the duel against McGonagall in Deathly Hallows, she would have put up a good fight, but he would have prevailed in the end due to his edge in the Dark Arts, Legilimency and Occlumency.
Sectumsempra was a curse invented by Severus Snape that lacerated the target and caused severe haemorrhaging. Snape created it as a student of Hogwarts, with the intention of using it against his enemies, likely including the Marauders, with it becoming one of his specialities.
Madam Rosmerta (fl. 1970s–2010s) was a British witch who was the landlady of the Three Broomsticks pub in the village of Hogsmeade. Rosmerta was put under the Imperius Curse, cast by Draco Malfoy in 1997.
Unfortunately, within the film universe's retelling, there is plenty of evidence there to suggest Ron used the Imperius Curse on Hermione so that she would fall for him.
However, despite being rescued by them, Griphook's general mistrust of wizardkind resulted in him betraying Harry Potter, Ron Weasley, and Hermione Granger. He betrayed them because he believed they would not hand him the Sword of Gryffindor, after destroying the Cup and other Horcruxes.
Weasley family patriarch Arthur was placed under the Imperius curse by Voldemort and his Death Eaters during the Dark Lord's rise to power, making him one of the few legitimate victims of the curse in a world where most of those who claimed they had been bewitched were just doing it to justify the actions they took ...
Unforgivable Curses are the three most powerful and sinister spells known to the wizarding world, and are tools of the Dark Arts. They were first classified as "Unforgivable" in 1717. They are the Killing Curse, Avada Kedavra, the Cruciatus Curse, Crucio, and the Imperius Curse, Imperio.
It is also said to be a fairly complicated spell. It depends on a persons willingness to kill someone and also the power behind the wand. To quote Barty Crouch/Mad-Eye Moody in 'Harry Potter and the Goblet of Fire', “Avada Kadavra is a curse that needs a powerful bit of magic behind it.
Of course, circumstances play an important role, as Bellatrix Lestrange manages to kill other powerful wizards such as Sirius Black through her occasionally unfair strategies, but in a proper one-on-one duel, Professor McGonagall would win.
During the Battle of Hogwarts, Voldemort used the Cruciatus Curse on what he believed to be Harry Potter's dead body as a way of dishonouring it and to show he had won. Harry felt no pain because the wand Voldemort used, the Elder Wand, refused to harm its true master.
Why didn't Harry use Avada Kedavra against Voldemort?
To Harry, Voldemort was the epitome of evil, as was the Killing Curse by extension, so he would not use the Unforgivable Curse that killed his parents. It's also believed that Avada Kedavra requires the caster to be willing to commit murder for the spell to work.
In the film version, Barty Crouch Jr. has the habit of licking his lips when threatened, in a snake-like way, to which he occasionally shows while under the disguise of Alastor Moody. This action led to him giving himself away to his father following the second task of the Triwizard Tournament.
Ron never cast any kind of curse on Nagini, not in the book anyways. And there's no confirmation that the spell he used on her in the movies was the Killing Curse. Avada Kedavra isn't the only spell that creates green light, after all.
But Ron Weasley is the exception, giving it a go in the Deathly Hallows: Part 2 movie when himself and Hermione look destined to die via Nagini. The curse just seems to go through Nagini like it's nothing whatsoever.
Originally Answered: In the Goblet of Fire book, the Avada Kedavra is described as unblockable. However, in the Deathly Hallows movie, Hermione blocks an Avada Kedavra curse aimed at her.
In the final movie, Harry Potter and the Deathly Hallows pt. 2, Molly first hits Bella with a spell that freezes her, most likely Petrificus Totalus. Then, she launches another one that shatters her entire body into pieces, which could be expelliarmus, bombarda, stupefy, or any spell that can produce such an effect.
As the youngest Weasley, we're sure Ginny observed more than her fair share of unpleasant spells over the years but it was the Bat Bogey Hex she was famous for – and with good reason. This was the spell that overpowered Draco Malfoy and the Inquisitorial Squad, and also secured her an invite to the Slug Club.
