Disruption spell

Incurso was an offensive spell that was used to hex opponents. Giles used this spell in his duel against Dark Willow. The spell required only an incantation, which roughly translates to "to attack" or "to invade" in Latin. The spell is cast through the caster's mouth and appears as a green gas that envelops its target. The spell causes magical damage or, at the very least, disruption. The effects of the spell was short-lived. Whether this was intrinsic to the spell or because it was used against an extremely powerful opponent, or both, is unknown.