Arcane Parasite

his spell creates a link between you and a nearby source of arcane power, allowing you to draw on its strength to bolster your spellcasting ability. When you cast a spell, you can use a bonus action to draw on the link. Doing so means you expend no spell slots to cast the spell, the energy instead comes from the external power. The more you draw on the link, the harder it is to maintain. Each spell you cast in this manner decreases the duration of the arcane parasite spell by 10 minutes per level of the spell you cast using the link. For example, if you cast a fireball spell using the link, you would not expend a spell slot in the casting, but the duration of this spell would decrease by 30 minutes. If you cast a spell using the link
 and your remaining duration is equal to or less than the spell’s level × 10 minutes, then this spell ends as soon as that spell is cast.