Helixa and Syna Hyslop
The Gemino Curse, known also as the Doubling Charm (Geminio) is a charm that enables the caster to create an identical twin to whatever they flick their wand at. The copies are absolutely worthless, and if the caster so desires, the object will multiply on touch for hours or even days on end.
The Doubling Charm was invented a very long time ago by twin witches Helixa and Syna Hyslop, who were very strange and reclusive. They had made twin sets of everything they owned, right down to hand-written instructions for the spell, which were eventually spread worldwide.
In 1998, the employees of Gringotts Wizard Bank used this spell on the treasures of the Lestrange Vault,ref name="DH26"/>, and Hermione Granger did the same to a locket belonging to Salazar Slytherin.
- Harry Potter and the Deathly Hallows
- Harry Potter and the Deathly Hallows: Part 2
- Wonderbook: Book of Spells