Vidden's Dissolution Resistance

The casting of this spell will consume two different spell slots:  the fourth level spell slot for this spell, and one to chosen in advance to be sacrificed by the caster.  The enchanter strengthens the resilience of a spell that is permanent until dispelled making it even harder to dispel the original spell effect.  During the casting of the spell, the caster chooses a spell slot that will be sacrificed to enhance the DC of the dispel check.  If the fourth level spell slot used to cast this spell is higher than the original spell slot, then the base DC of the spell becomes 14, until augmented by the sacrificed spell slot.  

For example, a caster uses True Polymorph on a target to turn the victim into a caged bird.  If someone were trying to Dispel the Shape change the target number would be 10 + the spell's level; a 19.  If this spell is cast and an 8th level spell slot was sacrificed, the DC for the dispel would be 27.  If the wizard used a Magic Mouth and wanted to make it harder to dispel, then the original DC to dispel the Magic Mouth would be 12 (10 plus the second level spell of Magic Mouth).  If this spell was used to strengthen the dispel resistance you would replace the second level spell slot with the fourth level spell slot from this casting, giving a base of 14, plus the spell slot chosen in advance to be sacrificed by the caster.  So a 5th level spell slot sacrificed would be a DC of 19 to dispel the magic mouth.