The Substantive Charm was a spell of unknown effect. The day before his O.W.L. exam for Charms, Seamus Finnigan laid on the floor reciting this spell's definition as his friend, Dean Thomas, confirmed it in The Standard Book of Spells, Grade Five.
Behind the scenes
- Given that the word "substantive" means 'solid' or 'existent', it is likely that this spell has such a use; it might possibly be used to solidify ghosts, hurting them in a similar way to Skurge.
- Harry Potter and the Order of the Phoenix (Mentioned only)