Rictusempra, the Perpetual Tickling charm, which apparently can be stopped by the Finite Incantatem charm, was used by Harry against Malfoy in the Duelling Club. The intent was, of course, to tickle Malfoy to the point that he would be unable to jinx Harry in return.
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.
It was first introduced in the book "Harry Potter and the Chamber of Secrets." The spell's incantation is "Rictusempra" and when cast, it can cause the target to become incapacitated with laughter, making it a useful spell for distraction or immobilization.
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.
Why Sectumsempra Isn't an UNFORGIVABLE Curse - Harry Potter Theory
Why is sectumsempra not unforgivable?
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.
Harry Potter used Unforgivable Curses, such as the Cruciatus Curse, in extreme situations of emotion and distress. Harry used the Imperius Curse multiple times during the Gringotts heist to accomplish their mission.
In his memoir, Felton said that Fiennes improvised Voldemort awkwardly hugging Draco Malfoy. "It gave me goosebumps then, and the memory gives me goosebumps now," Felton wrote.
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.
Lucius and Draco's crimes were forgiven due to their abandonment of Voldemort and his cause and Narcissa's lie to the Dark Lord that saved Harry Potter's life in the Forbidden Forest in the Battle of Hogwarts. None of them served time in Azkaban.
But many people forget that he also invented a number of spells. In the Harry Potter movies, Snape came up with the Sectumsempra curse when he was a student at Hogwarts, and it's known to cause painful lacerations on the target.
Rather than a spell, Priori Incantatem is an effect that occurs when two wands that have magical cores deriving from the same source are used against each other. One or the other of the wands is forced to regurgitate the last spells that it was used to cast. The effect is very similar to the spell Prior Incantato.
So why does Harry always use Expelliarmus? Well that would be just his natural reaction. From the wiki page harrypotter.wikia.com/wiki/Harry_Potter it says that Expelliarmus is his signature spell and would thus be his natural response to any attacks. Just like if person A trained the hammer fist a lot.
A form of magical defence, Salvio Hexia is a protective spell that is used to shield an area or an object from hexes or jinxes. This is a handy spell to know if a witch or wizard needs protection against dark magical attacks.
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.
It's implied that Septum Sempra is Snape's own creation, that he used a specific counter-curse to heal Draco, and that the spell isn't designed to be instantly fatal, but to inflict a gruesome, but relatively slow death if left untreated. It's likely Snape is the only person who knows said counter-curse.
Harry Potter had a few love interests during his time at Hogwarts. Though he eventually settled down with Ginny Weasley, he also had a thing for Cho Chang in his earlier school years. Then, of course, there's his secret love for Draco Malfoy…
As Draco is about to pass him, Voldemort stops Draco to congratulate him on making the right decision. But, the encounter doesn't stop there, as Voldemort gives Draco a hug. The moment is easily one of the most awkward scenes in the entire Harry Potter franchise and often criticized for being just that.
J.K. Rowling said that Draco had a crush on Hermione Granger, but he doesn't show that, beacuse Hermione was a Gryffindor, Harry's friend, and also a muggle-born. After the Battle for Hogwarts, Draco fell in love with Astoria Greengrass, and they had son Scorpius.
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.
Harry Potter used the curse three times on two different individuals in order for the Trio to break into Gringotts Wizarding Bank undetected. Minerva McGonagall used it to force Amycus Carrow to bind himself and his sister.
