Magic catalysts can exist in various forms, from thrown potions to wearable items. Catalysts contain ingredients or are charged with magical power that can be used with minimal or no drain of the user's magical energy. During her initial fights with Negi, for example, Evangeline McDowell threw several catalyst potions to cast her spells, compensating for her mostly-sealed magical power. Negi used them on his own in the subsequent battle against her, in order to conserve his own energy.