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.
Malfoy spots Harry and casts a Cruciatus curse; Harry, defending himself, using the Half-Blood Prince's Sectumsempra spell without knowing its effects. To his horror, it gashes Draco's face and chest, spilling his blood everywhere. Moaning Myrtle flies off, screaming.
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.
Sectumsempra is a curse invented by Professor Severus Snape, during his childhood, when he was known as "The Half-Blood Prince". He created it with the intention of using it against his enemies, and it soon became one of his specialties.
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.
How Snape Made Sectumsempra and HOW Spells are Created - Harry Potter Theory
Why doesn'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.
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.
The injury was caused by Snape's Sectumsempra spell in order to stop the Death Eaters from hurting George (who he thought was Harry) and Lupin, but missed and hit George. Hermione and Kingsley then arrived, both unharmed, followed by Arthur and Fred Weasley, both concerned for George.
The Disarming Charm became Harry Potter's signature spell, and it notably caused the final defeat of Lord Voldemort during the Battle of Hogwarts by rebounding his Killing Curse, because the Elder Wand recognised Harry as its master through the spell connection, and thus strengthened the Disarming Charm to the point ...
A rather dangerous curse, when the incantation was uttered, its effect was the equivalent of an invisible sword; it was used to slash the victim from a distance, and resulted in deep wounds. The slash followed the user's wand movements.
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.
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.
Although it is not confirmed to have been the Killing Curse, it is highly likely that Ron attempted to kill Voldemort's snake, and last Horcrux, Nagini, with Avada Kedavra. This is because, in the movies, Ron can be seen firing out a green spell at the snake, and it looks just like the Killing Curse.
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").
In order to truly prove himself, Draco must kill Albus Dumbledore and pave the way for the Death Eaters to enter Hogwarts. Snape promises to protect Draco and spare him from a task that would almost certainly scar him for life, and they seal the promise with an Unbreakable Vow.
That same year, Aragog contracted an unknown illness over the summer, and despite Hagrid's attempts to heal and comfort Aragog by feeding him giant grubs, he eventually died on 20 April 1997.
One of the three Unforgivable Curses outlawed under wizarding law, Avada Kedavra kills the victim on impact, instantaneously and painlessly, usually with a blinding flash of green light. There is no way to block the spell, and there is no counter-curse - it can only be dodged.
The Killing Curse is a spell that causes instantaneous death and is one of the three Unforgivable Curses. Its incantation is Avada Kedavra. The only known counter-spell is sacrificial protection, which uses the magic of love. However, one may dodge the green bolt or block it with a physical barrier.
In the film, Bellatrix casts a blue spell at Ginny Weasley instead of a Killing Curse, who deflects it using a Shield Charm. In the book she just avoids it.
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.
This theory became so popular that even Pottermore indicates that Flipendo is the Knockback Jinx's incantation on its list of spells. However, the term Flipendo had not yet been used in any official Harry Potter publication… but that was all about to change with the Wizarding World's expansion into a new medium.
