Andrui's Baneful Backfire (EFA - A)

Through this spell you protect your belongings from tampering by other spellcasters. You cast it on any magical item you possess. It remains dormant until dispel magic is cast on the object.

When that happens, the dispel attempt automatically fails, and the caster loses one of their highest-level spell slots. For example, if you cast the backfire on a door on which you had also cast arcane lock, when another spellcaster attempts to dispel your arcane lock, the backfire will cause not only the dispel attempt to fail, but the caster to lose one of their highest-level spell slots.