Antonin Dolohov's curse

"But the Death Eater… made a sudden slashing movement with his wand from which flew a streak of what looked like purple flame. It passed right across Hermione’s chest; she gave a tiny “oh!” as though of surprise and then crumpled onto the floor."

- Antonin Dolohov casting this curse nonverbally on Hermione Granger during the Battle of the Department of Mysteries

This curse (incantation unknown) was used by the Death Eater Antonin Dolohov during the Battle of the Department of Mysteries in 1996. The curse is cast using "a sudden slashing movement with the wand," causing a streak of purple flame to strike the target. Given its exclusively harmful effects, it is presumed to be Dark magic.

Effects
The effects of this Dark curse are unknown, but it is very dangerous and potentially lethal. Given that Hermione Granger had no visible marks or bleeding from her injury with this curse, but exhibited soreness for some time afterward, it is probable that the curse causes some kind of painful internal injury.

Known uses
"A whine of panic inside his head was preventing him thinking properly: he had one hand on Hermione's shoulder, which was still warm, yet did not dare look at her properly. Don't let her be dead, don't let her be dead, it's my fault if she's dead... Neville groped for Hermione's wrist. "Dat's a pulse, Harry, I'b sure id is." Such a powerful wave of relief swept through Harry that for a moment he felt light-headed."

- Harry Potter and Neville Longbottom after Hermione Granger was hit with the curse

Antonin Dolohov used the curse twice during the Battle of the Department of Mysteries, first against Hermione Granger, who was knocked unconscious but survived. Dolohov might have killed Hermione if he had been able to say the incantation, but his voice was taken by Hermione's Silencing Charm earlier in the battle and the nonverbal version of the curse was not as powerful as it normally would be.

Hermione's Recovery
"She winced slightly and put a hand to her ribs. The curse Dolohov had used on her, though less effective than it would have been had he been able to say the incantation aloud, had nevertheless caused, in Madam Pomfrey's words, "quite enough damage to be going on with." Hermione was having to take ten different types of potion every day..."

- Description of Hermione Granger's recovery from a nonverbal use of this curse Afterward, Hermione had to take no less than ten different potions daily for an extended period of time, provided by the Hogwarts nurse Madam Pomfrey.

Other Uses
Dolohov used the curse again against Harry Potter later in the battle, but it was blunted by Harry's use of the Shield Charm. Harry described it as a "streak across his face like a blunt knife," and the force of the curse knocked him off his feet. Dolohov also attempted to use the curse against Sirius Black while they were duelling during the battle, but Harry managed to hit him with a Full Body-Bind Curse before he could complete the spell.

This may be the curse Dolohov used to kill Remus Lupin during the Battle of Hogwarts, as it is noted that Remus's body was peaceful-looking, and this curse is not known to cause any visible signs of damage.

Appearances

 * Harry Potter and the Order of the Phoenix