This powder affects one medium-sized creature or object, reversing any spell cast on the subject for 24 hours. Spells that are reversible (such as bless or cure light wounds) have the opposite effect on the target of the powder. This applies to currently operating spells, and those cast on the target during the duration. Spells currently affecting the target that are not reversible are negated as per dispel magic. Spells cast at the target that are not reversible are negated, making the target immune to such effects for the duration.