Magical tattoos, requested by doitinthelibrary
Long before the concept of tattoos appeared in the Wizarding World there were those who made permanent markers on their bodies: messages, seen by everyone, or few; words of protection, and warnings, invisible until a specific curse, or death; consequences of spells and potions gone wrong; objects transformed into ink and hidden under the skin. Not many could wield such magic, and stories of those who could had changed over the time. The wizarding world wanted something tangible, controllable: amulets, cloaks, wands.
It came back as a form of art, to use bodies as carcasses for motionless, or breathing, moving, even having minds of their own, pictures. Many disapproved, of course. After all, like everything else ever invented by a wizard, it could’ve been abused and misused - and it was, once Tom Riddle, always so fascinated with the old practices, figured out a way to use it for communication between his followers. His opponents disregarded it as Dark Magic, and refused to hear anything about adopting the idea and using it against the Death Eaters.
Things changed after the war. With two cultures slowly merging Muggleborns brought the fashion of their world along with them, and it found support among those claiming to had been under Imperio who now wished to cover the Dark Mark. Old teachings got adapted into spells, written down, and catalogued, for anyone to learn and apply. With that, lost its charm, the practice did, some say.
Young wizards and witches laugh at this notion, of course. Secrets, available to a chosen few, breeding misconceptions and fears, - nothing’s ever charming about that.