Spell: Prior Incantato

Pronunciation: Pry-or in-can-tah-to

Use: To force a wand to show an 'echo' of the previous spell it has performed

Mention(s): In the Goblet of Fire Amos Diggory uses this spell on Harry's wand to prove it was used to cast a Dark Mark in the sky

Fact(s): If a killing curse is echoed a ghost like form of the person killed with emerge from the wand

Note(s): In rare instances when two wands with cores from the same animal are forced to duel against one another, this will manifest in Prior Incantatem. When one wand overpowers the other, it will force the losing wand to regurgitate 'echoes' of the most recent spells it has cast