Dark Mark

"...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 inside... Everyone’s worst fear...the very worst."

- Arthur Weasley

The Dark Mark is the symbol of Lord Voldemort and his Death Eaters. It refers both to a magically induced brand that every Death Eater bears on his or her inner left forearm, and to the same symbol conjured in the air by the spell Morsmordre.

Appearance
The Dark Mark appears as a glittering green skull with a snake protruding from its mouth. This might have been inspired by the hiding place of the Basilisk in the Chamber of Secrets. When summoned, the basilisk would emerge from the mouth of Salazar Slytherin. The serpent is also the symbol of Slytherin house, and thus appropriate to be used by the Heir of Slytherin.

The symbol might also be related to the fact that Lord Voldemort was a Parselmouth, a gift he thought made him unlike the rest of the wizarding world. The Dark Mark on the forearm is black, while the Dark Mark conjured by Morsmordre is green, this is most likely for more contrast with each respective background as a black Dark Mark would be hard to see in the night sky.

On the arm
"The werewolf might be allowed to wear Death Eater robes when they wanted to use him, but only Voldemort's inner circle were branded with the Dark Mark: Greyback had not been granted this highest honour."

- Harry Potter on Fenrir Greyback's lack of a Dark Mark

An inactive Dark Mark appears as a faint mark on the inner part of the left forearm, similar to that of "a vivid red tattoo"; an active one is jet black.

Lord Voldemort placed the Dark Mark brand on his followers' inner left forearms both as a sign of their loyalty to him and as a method of summoning them to him when he desired. This was done by pressing his wand to any Death Eater's Mark, which turns it jet black and delivers a burning sensation to any person with the Dark Mark. Feeling the burn, the Death Eaters then Apparate to Voldemort's side. When Voldemort was regaining his strength after his first defeat, the faded marks were getting clearer, and were burning slightly, a sign of their master's impending return. Death Eaters could also use it to signal Voldemort by pressing on their Dark Marks. Bearing this mark also allows the Death Eaters to bypass a cursed barrier that is also invented by Voldemort. During the height of the Second Wizarding War, they were under orders to only signal Voldemort if they had successfully captured Harry Potter, or face severe penalties. After Voldemort was defeated for the final time, the dark marks faded to a scar, similar to Harry's lightning-bolt scar. They would no longer burn, but would remain nevertheless. There is no possible way of getting rid of the Dark Mark.

Only Voldemort's inner circle were branded with the Dark Mark, which was considered a great honour among his followers. Thus, people like the Snatchers never received one.

Hermione Granger used the Protean Charm to create special coins for Dumbledore's Army, which would heat up when signaling a meeting, and she claimed that she indeed got the idea from the Dark Mark. However, instead of burning them onto the members' arms, she decided to use coins, something that Harry agreed was better.

In the sky
As a signature of their work, the Death Eaters can also use a spell to create an image of the Dark Mark in the sky. The incantation of this spell is Morsmordre. The appearance of the one in the sky is basically the same as the one on the forearm, but green in colour.

Notable uses include in the woods during the 1994 Quidditch World Cup Final, when it was cast by Barty Crouch Jr., and over the Astronomy Tower of Hogwarts School of Witchcraft and Wizardry by Gibbon in 1997. It normally appears where there has been death by the hands of Death Eaters or Lord Voldemort.

The other form of the Dark Mark has been seen when Voldemort touches the Dark Mark branded on an arm, a skull forms in the sky above and the alerted Death Eaters apparate out of its mouth instead of a snake.

Behind the scenes

 * Fred and George Weasley created Edible Dark Mark for their joke shop.
 * The Dark Mark in the sky and on the Death Eaters' arms are different in appearance. The one in the sky is plainly a skull with a snake coming out straight out of its mouth, while the brand on a Death Eater's arm is much more intricate and detailed, the snake being much longer and winding.
 * The spells used to brand and conjure the Dark Mark were likely invented by Lord Voldemort. He may have based the spell on the Protean Charm, as Hermione Granger mentioned in 1995 that the Dark Mark inspired her to use the Protean Charm to create the method of communication used by Dumbledore's Army.
 * Peter Pettigrew, despite being a low-ranking soldier for his cowardice and lacking skills, is branded with a Dark Mark. However, he is not given the same respect as the other Death Eaters would receive, and is instead treated as a lowly household servant by both his master and his colleagues. Voldemort would use it shortly after his resurrection to summon his other Death Eaters
 * When Harry mentions that the Dumbledore's Army coin reminds him of the Death Eaters' brands, he incorrectly refers to the brand as a scar.
 * In Harry Potter and the Half-Blood Prince, the Dark Mark is cast by Gibbon in order to lure Dumbledore to the Astronomy Tower. In the film version, the Mark is cast by Bellatrix Lestrange in celebration after Dumbledore's death.
 * In the beginning of the fourth film, the skull and snake appear as a green glowing light, brightening like an Aurora, while later in the same film and twice in the sixth film, the skull is moulded from the clouds. There also seems to be no serpent jutting out of the mouth of the skull.
 * At the near end of the fourth film, when Barty Jr. held Harry inside his office, he kept rubbing Harry's wound where Pettigrew cut him, using the blood to form a crude form of the Dark Mark.
 * In the books and in the back cover of the Scholastic edition of Harry Potter and the Half-Blood Prince, the Dark Mark is depicted by Mary GrandPré as being a group of green glowing stars, like a monstrous constellation. Otherwise in the movie adaptations, they are either shaped from the clouds or made of glittering green light
 * In the film adaptation of Harry Potter and the Half-Blood Prince, Draco Malfoy openly displays his Dark Mark to Albus Dumbledore. In the novel, it is not verified that Draco received the Mark, though it was highly speculated by Harry Potter that it was what Draco showed Borgin as a form of intimidation.
 * In LEGO Harry Potter Years 1-4, during the Quidditch World Cup, you can see the shadow of Barty Crouch Jr when the ring of fire comes, Death Eaters stay and attack, however, they flee in the book and movie.
 * The Dark Mark has been used on both the J. K. Rowling Official Site and Pottermore to indicate content of a spoilerish nature.
 * During the Second World War, members of the Nazis paramilitary organization the Waffen-SS had their blood group tattooed on their inner left arm.  During the immediate aftermath of the war, this was used to identify fugitive SS men. This may be the inspiration for the Dark Mark.

Appearances

 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Goblet of Fire (film)
 * Harry Potter and the Goblet of Fire (video game)
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Order of the Phoenix (film)
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter and the Half-Blood Prince (video game)
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 1
 * Harry Potter and the Deathly Hallows: Part 1 (video game)
 * Harry Potter and the Deathly Hallows: Part 2
 * Harry Potter and the Deathly Hallows: Part 2 (video game)
 * Harry Potter: A Pop-Up Book
 * LEGO Harry Potter: Years 1-4
 * J. K. Rowling Official Site
 * Pottermore

Notes and references
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