EDIBLE DARK MARKS----THEY'LL MAKE ANYONE SICK!
-- Sign on a tub in Weasley's Wizard Wheezes in Diagon Alley (HBP6)
Sickening sweets based on the tattoos of Voldemort’s followers (HBP6) Sold by Weasleys Wizard Wheezes in Diagon Alley.
The cheeky Weasley Twins were being brave to mock the Dark Lord in this fashion -- rather like whistling past the graveyard. It's amazing they could get away with being so cheeky while Death Eaters like Draco Malfoy visited their store. Perhaps the only thing that saved them was the usefulness of their other supplies to Voldemort's cause, such as the Peruvian Darkness Powder used in the Battle of the Tower (HBP29).