Protean Charm

The Protean Charm is a charm that links several objects together. Hermione Granger used this charm during Harry Potter's fifth year at Hogwarts (Harry Potter and the Order of the Phoenix) to communicate with the members of Dumbledore's Army (D. A.) using coins disgused as Galleons. Ravenclaw Terry Boot had commented that the charm was N. E. W. T. standard. The coins (still under the Protean Charm) would be used from the time they were introduced until the D. A. is discovered by current Defense Against the Dark Arts teacher Dolores Umbridge. They would be mentioned in the Half-Blood Prince when Hogwarts fell under attack by Death Eaters and Ron Weasely and Hermione attempted to summon help (only Nevelle Longbottom and Luna Lovegood would respond, as they continued to check their coins for potential D. A. meetings). They would make their last apperence at the end of Deathly Hallows when the D. A., in hiding in the Room of Requirement, had summoned every member to attempt a retaliation for the harsh conditions at Hogwarts under Headmaster Severus Snape before the Battle of Hogwarts.