Desecrated Tomb

Most graveyard payoffs trigger when cards enter the yard; this one watches the other door. The trigger fires when creature cards leave your graveyard, which reframes every recursion spell, every reanimation effect, and every graveyard-based cost as a source of free bodies. That inversion is the whole pitch. A card that returns a creature to your hand or battlefield was already doing its job; this converts the side effect (a creature leaving the graveyard) into a Bat, at no extra mana. The payoff scales with how aggressively a deck churns through its own yard, so the design rewards builds that treat the graveyard as a resource to spend on loop after loop, not a place where dead things rest. Note the precision of the wording: it counts creature cards, not creatures, and it counts the event of one or more leaving at once, so a single mass-recursion spell that returns four creatures still makes only one Bat, while four separate recursions make four. That clause is what keeps it from spiraling. It does nothing the turn it resolves, asking instead for a board built to feed it: Unearth and escape creatures cycling back into play, scavenge and embalm spending bodies from the yard, self-mill loops refilling it. The Bats themselves are almost incidental, small and evasive, best understood as the receipt for a graveyard that never stops moving.