Cruciatus Curse

"Pain. You don't need thumbscrews or knives to torture someone if you can perform the Cruciatus Curse.... That one was very popular once too."

- Barty Crouch, Jr. as Alastor Moody

The Cruciatus Curse (also known as the Torture Curse ) is one of the three Unforgivable Curses of the wizarding world. It is a curse of torture, inflicting excruciating pain on a victim. This makes it popular among the Death Eaters for use on both fellow wizards and Muggles. Considering the fact that this curse doesn't physically harm the victim, it is possible that it only stimulates pain receptors. It is considered to be the worst one of the three.

The two most well-known victims of this curse are the former Aurors Alice and Frank Longbottom, who were tortured into insanity with it by Death Eaters Bellatrix, Rodolphus, Rabastan Lestrange, and Barty Crouch Jr.

Harry also used this curse on Bellatrix.

Performance
"You need to mean them, Potter! You need to really want to cause pain ... to enjoy it ... righteous anger won't hurt me for long ... I'll show you how it is done, shall I? I'll give you a lesson -"

- Bellatrix Lestrange to Harry Potter

To successfully perform this curse, the wizard or witch must possess a deep desire to cause the victim pain. For example, despite being furious with Bellatrix Lestrange for her murder of his godfather in 1996, Harry Potter was only able to cause her a brief moment of pain with the Cruciatus Curse because he used it in "righteous anger," though he was still able to knock her off of her feet with it. He performed it more powerfully in 1998 on Amycus Carrow, who spat in Minerva McGonagall's face. Amycus was thrown into the air and knocked unconscious. This may suggest that although Harry's curse was intense, he still lacked the fundamental sadism to inflict prolonged, excruciating pain with it. On the other hand, due to Bellatrix being a witch with great sadistic intents and no conscience, she was able to cast the curse with great potency, and seemingly have an affinity to it.

Effects
"At once, the spider's legs bent in upon its body; it rolled over and began to twitch horribly, rocking from side to side. No sound came from it, but Harry was sure that if it could have given voice, it would have been screaming. Moody did not remove his wand, and the spider started to shudder and jerk more violently..."

- Description of a spider under the Cruciatus Curse

The pain caused by the Cruciatus Curse is said to be worse than "one thousand white-hot knives, boring into the skin." This pain can cause permanent mental injury, as in the case of the aforementioned Longbottoms, who spent the rest of their lives in St Mungo's Hospital for Magical Maladies and Injuries because of the trauma the curse caused. Presumably, such permanent effects occur if the victim is exposed to a particularly intense curse for a long period of time.

If the curse hits an inanimate object, it may cause it to shatter instead.

Creation
The Cruciatus Curse was invented during the early middle ages, by dark witches or wizards. The curse was created for torture purposes, but has also been used effectively in duels. According to Barty Crouch Jr., the curse was once very popular.

Legal Status
"The Cruciatus, Imperius and Avada Kedavra Curses were not made "unforgivable" until 1717."

- Albus Dumbledore

After the Wizards' Council was reformed into the Ministry of Magic tighter restrictions were placed on the use of certain kinds of magic. The Cruciatus Curse was deemed by the Ministry to be dark magic, and, along with the Imperius and Killing curses, were declared "unforgivable" in 1717. The use of any of these three curses on a fellow human being would result in a life sentence in Azkaban (unless there was sufficient evidence that the caster did so under the influence of the Imperius Curse or for other defensible reasons).

During the First Wizarding War, when Barty Crouch Sr. was in charge of the Department of Magical Law Enforcement, he fought violence with violence, and legalised the three Unforgivable Curses for Aurors against the Death Eaters in order to win the war. This was repealed once the war was over, as it was no longer necessary. However, in the 1994–1995 school year, Barty Crouch Jr., under the disguise of Alastor Moody, showed these three curses to his fourth year classes on spiders despite the Ministry's disapproval. However, since the use of the curse was illegal only on a fellow human being, the demonstration of the curses on the spider may have been within legal boundaries.

When Lord Voldemort took over the Ministry, the three curses were once again legalised: this time every wizard and witch had the right to use them as they please. In fact, they were practiced in Hogwarts as part of the curriculum of Dark Arts class under the tutelage of Professor Amycus Carrow: students were required to practice the Cruciatus Curse on other students who earned detention, and the Carrow siblings used it to punish students as they see fit. Harry Potter managed to succesfully use it on Amycus Carrow without legal consequences as well as a result of this legalization. After Voldemort's death and the revolutionising of the Ministry under Minister Kingsley Shacklebolt, the three curses were once again forbidden.

Possible uses

 * Harry Potter had a vision of Lord Voldemort ordering Draco Malfoy to use the curse on Thorfinn Rowle after he and Antonin Dolohov failed to capture Harry at Tottenham Court Road. Although he saw nothing of Dolohov's punishment, Narcissa Malfoy later mentioned "what he did to Rowle and Dolohov" when she was afraid to contact Voldemort, making it likely that Dolohov was subjected to the Cruciatus Curse as well.
 * As Harry Potter chases Severus Snape away from Hogwarts at the end of the Battle of the Astronomy Tower, he is hit from behind by a curse cast by one of the Carrow siblings. Although we never hear the incantation, he falls to the ground, screaming, and momentarily loses track of what's going on. This description, coupled with the fact that the Carrows had been trying to curse him all the way down from the Astronomy Tower, makes it likely that he was hit by the Cruciatus Curse.
 * Since Luna was held prisoner at Malfoy Manor for months, it is likely she was also tortured with it.
 * After Harry, Ron, Hermione, and the other prisoners escaped from Malfoy Manor, Harry had a vision of Voldemort punishing Bellatrix Lestrange and the Malfoys, but whether he used the Cruciatus Curse was not mentioned.

Etymology
Crucio means 'I torture'. Cruciatus takes its name from the Latin word for "pain" or "torture," the root of which can be seen in other words such as "excruciating" and "crucifixion."

Behind the scenes

 * When Harry Potter attempts to cast this spell on Bellatrix Lestrange, a ball of red light is fired from the tip of his wand.
 * Severus Snape once asserted Harry Potter had neither the nerves nor the skill to perform Unforgivable Curses. However, less than a year later, Harry succeeded in cursing Amycus Carrow. - This move was met with criticism by some fans, who felt that Harry had sunk to the same level as his enemies in using it in such a manner. J.K. Rowling countered such criticism by asserting that "Harry is not, and never has been, a saint", and that he has flaws of character like everybody else.
 * In the original script of the film adaptation of Harry Potter and the Half-Blood Prince, Harry Potter said "Cruciatus" while battling Severus Snape in Hogwarts grounds instead of using the real incantation which is "Crucio." In addition, in Harry Potter and the Order of the Phoenix, in Harry's vision of Voldemort and Sirius at the Department of Ministries, Voldemort's pronunciation seems to be "Crucius" but it is muddled by the crackling sound of the curse affecting Sirius. But it is possible this could still happen to Sirius since it was a vision created by Voldemort and not real.
 * In Lego Harry Potter: Years 1-4, only Dark Wizards, including Peter Pettigrew, Lord Voldemort, and Barty Crouch Jr. can use Dark Magic, which consists of the Killing Curse (Peter Pettigrew is the only lego dark wizard who can't use avada kadavra) and the Cruciatus curse. Whenever a Dark Wizard uses Wingardium Leviosa on a person, it instead changes to the Cruciatus curse. When this is used, the victim hovers several feet off the ground, and purple lights emits from their joints. After a few seconds, they die.
 * According to the W.O.M.B.A.T. test, it is unknown if there is a defensive charm for the Cruciatus Curse, however Snape is able to parry it in Half-Blood Prince.

Appearances

 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Goblet of Fire (film)
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Order of the Phoenix (film)
 * Harry Potter and the Order of the Phoenix (video game)
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 2
 * Lego Harry Potter: Years 1-4
 * Harry Potter: Spells

Notes and references
Cruciatus-Fluch Doloris