Point wand in the sky 
Conjures the Dark Mark
- Ronald Weasley: "I don't get it, I mean... it's still only a shape in the sky..."
- Arthur Weasley: "Ron, You-Know-Who and his followers sent the Dark Mark into the air whenever they killed. The terror it inspired... you have no idea, you're too young. Just picture coming home, and finding the Dark Mark hovering over your house, and knowing what you're about to find... Everyone's worst fear... the very worst..."
- — Ron and Arthur Weasley discussing the Dark Mark.[src]
Morsmordre is the incantation of the curse used to conjure the Dark Mark, the skull-and-serpent sign used by Voldemort and his Death Eaters. It is very likely that Voldemort invented this piece of magic and taught it to his followers. Only Death Eaters and Lord Voldemort know the correct way to cast the spell, although Horace Slughorn is implied to know how to cast the spell as well. Death Eaters often cast it after committing a murder, placing the Dark Mark in the sky over the location of the victim's corpse. It is against the law to cast this spell, even though, beyond its symbolic impact, there's no indication the spell causes any physical damage.
Barty Crouch Jr used this spell to set off the Dark Mark during the 1994 Quidditch World Cup using Harry Potter's wand, in order to scare the Death Eaters who were disloyal to Voldemort. At first, the house-elf Winky was blamed for the act until the truth was revealed by Crouch himself under the influence of Veritaserum.
It was cast over Hogwarts' Astronomy Tower by Gibbon when the Death Eaters invaded the castle in 1997, in order to lure Albus Dumbledore to the tower so that Draco Malfoy could kill him. However, it was Severus Snape who committed the murder, and Dumbledore's corpse was described to have fallen off the tower under the Mark's eerie green light like a great rag doll.
EtymologyThe incantation of this spell appears to be derived from the French mort, "death", and mordre, "to bite". This alludes to the name of Voldemort's followers, the Death Eaters. The English word murder could also contribute. In Norwegian, Morsmordere directly translated means "mothers killers".
It may also be a reference to the word "mord", which means "murder" in Icelandic, German, Norwegian, Danish Polish and Swedish, since the spell is cast after someone has been murdered, and sounds like "mass murder".
Behind the scenes
- In the film version of Harry Potter and the Goblet of Fire, the Dark Mark only appears greenish when it was cast at the Quidditch World Cup. When cast later in the same film after Voldemort's resurrection, along with its appearances in the film version of Harry Potter and the Half-Blood Prince, it appears to be formed out of dark grey clouds.
- In the book version of Harry Potter and the Goblet of Fire, the Dark Mark was cast over the Quidditch World Cup by Bartemius Crouch Jr. in order to strike fear at disloyal Death Eaters during their torturing of the Roberts family. However, in the film version, the Mark was cast after the Death Eaters destroyed the campsite, as a sign of the Death Eaters' works.
- In the book version of Harry Potter and the Half-Blood Prince, the Dark Mark was cast over the Astronomy Tower by Gibbon in order to lure Dumbledore there. However, in the film version, the Mark was non-verbally cast by Bellatrix Lestrange in celebration after Dumbledore was killed. Furthermore, in the film the Mark was dispelled by the mourning residents of Hogwarts as a sign of respect for the late headmaster.
- This is the only spell that Bartemius Crouch, Jr casts in his true form before becoming Alastor Moody by means of Polyjuice Potion
- Harry Potter: Spells shows the hand movement to be thus:
- Harry Potter and the Goblet of Fire (First appearance)
- Harry Potter and the Goblet of Fire (film)
- Harry Potter and the Goblet of Fire (video game)
- Harry Potter and the Half-Blood Prince
- Harry Potter and the Half-Blood Prince (film)
- Harry Potter and the Deathly Hallows: Part 1 (Seen in the Daily Prophet) (Heard)
- Harry Potter and the Deathly Hallows: Part 2
- Harry Potter and the Forbidden Journey
- Harry Potter: Spells