Stitch a little doll of the enemy army: the first time your opponent captures one of your pieces, a random enemy piece of the very same type is destroyed in sympathy. Kings are never harmed.
You draft Voodoo Doll in Buff mode. Passive: it works on its own the whole time you hold it, with nothing to activate.
As a attack card, it removes or detonates a piece directly.
“Ouch. Why did that hurt me.”