Aether Bindings of the Third Age Rainbow Foil (ROS163) - Rosetta

Instant -- Destroy this: Until end of turn, whenever an aura permanent you control with Sigil in its name leaves the arena, amp 1. (The next time you would deal arcane damage this turn, instead deal that much plus 1.) Battleworn (When the combat chain closes, if this defended, put a -1[Defense] counter on it.)