Caedarus is an incantation used to issue a tiny spark from the caster's wand; the spark will expand rapidly into a solid-looking sphere which can be used to strike a target.
Larry Albo used the incantation in a duel with Alexandra Quick in December 2008.
He later used the same incantation to win a duel against Quick in the Fall of 2009.
During the Fall of 2010, Albo regularly used the spell to defeat Quick during Dueling Club matches. Quick later used the spell in January 2011 against a man in Farewell, New Mexico.