The professor drew his wand, and muttered an incantation that "sounded almost like a song." He performed this counter-curse three times and with that, Draco was lifted into a standing position. Snape informed him he still needed to go to the hospital, and ordered Harry to stay behind.
Vulnera Sanentur was the song-like incantation of a healing spell which was used to heal deep wounds, which could also be used as the counter-curse for the curse Sectumsempra.
Minor wounds inflicted by this curse can be cured by the song-like incantation Vulnera Sanentur; the first usage eased the blood flow, the second caused the wounds to knit and the third removed the worst effects of the curse.
While Severus Snape was trying to cut the hand of a fellow Death Eater, he accidentally used a Sectumsempra Curse to slice George Weasley's ear. This dark magic spell, which Snape created during his student years at Hogwarts, is a curse that slashes through the skin like a sword and causes great bleeding.
There is likely a good reason that the Sectumsempra is not an unforgivable curse. It's mostly because Sectumsempra is Snape's personal curse that he created. It is not a widely known or used spell, and it is one that he kept secret — which means it can't be added to the list since no one really knows about it.
All 13 Times Severus Snape SAVED Harry - Harry Potter Explained
Why didn't Harry get in trouble for using sectumsempra?
When Harry critically injured Draco Malfoy with the Sectumsempra curse, it was actually enough to have him expelled, as Professor Minerva McGonagall stated Harry was lucky not to have been, due to Snape giving lenience to prevent others from finding out that he was the one who invented the curse.
Vulnera Sanentur was the song-like incantation of a healing spell and counter-curse to the Sectumsempra Spell, which was invented by Severus Snape. While sectumsempra was invented by Snape, Vulnera Sanentur is often mistaken to be invented by him as well.
George Weasley and Remus Lupin arrived next, and Molly attempted to heal George's wound; he recovered, but his left ear could not be healed because the wound was caused by Dark magic.
In Harry Potter and the Deathly Hallows: Part 2 and subsequent video game adaptations, this event takes place in the Boathouse instead of the Shrieking Shack. Instead of lowering the protective orb over Snape, Voldemort instead slashed his throat, and then had Nagini attack the weakened Snape.
Harry Potter's use on Draco Malfoy in the Duelling Club. The Tickling Charm (Rictusempra), also known as the Rictusempra Charm, is a spell that causes a victim to buckle with laughter. It also has at least two other side effects on the victim. It is usually used as a diversionary tactic in duels.
In the case of Snape. he was Sorted into Slytherin because he was ambitious, leaning towards the Dark Arts, his mother was one, AND he had an anti-Muggle bias, same as Salazar Slytherin himself.
Family. Snape's family background is mostly shown in flashbacks during the course of the last three novels. Snape was born to Eileen Prince, a witch, and Tobias Snape, a Muggle, making him a half-blood (hence the name, "Half-Blood Prince").
What was Harry's punishment for using Sectumsempra?
For using Dark Magic, albeit unknowingly, to cause serious harm, Snape sentences Harry to detention every Saturday until school ends. Snape dismisses Harry's protests, as does Professor McGonagall, who later informs Harry that he was lucky not to be expelled.
Though the aforementioned healing spell may heal the wounds and dittany may prevent scars, any body parts that have been severed by this curse cannot be grown back (a trait of dark magic's permanent effects), as demonstrated by George Weasley when he had his left ear cursed off due to the spell.
In Harry Potter and the Deathly Hallows, Fred and George are members of the Order of the Phoenix and serve as two of Harry's six decoys when he escapes Privet Drive. George loses one of his ears to Snape's Sectumsempra curse (which was aimed at a Death Eater's wand hand, but missed).
Harry describes Umbridge to Sirius Black, saying that she's vile enough to be a Death Eater, despite not being one. Umbridge is also depicted to be a prejudiced person, despising half-breeds and Muggle-born witches and wizards to the point of firing Hagrid due to his half-giant birth status.
According to the films, Hedwig's killer might have been Selwyn, who was known to be pursuing Harry and Hagrid at the time since Hedwig's death in the film happened quite a while into the fight when there was only a couple death eaters following them, or it might have been Stanley Shunpike under the Imperius Curse.
How did the Death Eaters know which was the real Harry?
When he spotted Stan Shunpike, who was only acting under the Imperius Curse, Harry did not want to hurt him, and thus tried to disarm him. The Death Eaters considered this Harry's "trademark" spell, and thus broke off pursuit, knowing he was the real Harry.
How did the Death Eaters know when Harry was being moved?
At Malfoy Manor, Snape tells Voldemort the date that Harry's friends are planning to move him from the house on Privet Drive to a new safe location, so that Voldemort can capture Harry en route.
Although healing magic could usually heal injuries without scarring, with dittany being one of the more effective, injuries caused by Dark Magic usually left scars that could not be healed, as Severus Snape expressed possibility that Draco Malfoy may have had some scars from the Sectumsempra curse, and Bill's scars ...
And Finally, knowing that Sectumsempra is a curse, and curses can't be cure with any charm, this makes the Vulnera Sanentur the only charm capable of Cure curses, And Snape the Only and Last person to know the Countercursel Because he Invented it.
Yes, he did. Against Severus, who blocked the spell. Or curse, if you prefer. The excuse Harry had for using it the first time “I didn't know what it could do" can't be used to justify his use of it a second time, when he knew full well what he could do.
As vile as this fight was, the question remains whether Snape gashed James' face using Sectumsempra. The short answer is no. While yes Snape did gash the side of James' face, Sectumsempra is a far deadlier curse.
