Instantáneo
Hasta una criatura objetivo obtiene -1/-1 hasta el final del turno. Creas una ficha de criatura Rata negra 1/1 con "Esta criatura no puede bloquear".
You can cast Rat Out without a target just to create a Rat token. However, if you do choose a target, and that target is illegal at the time Rat Out tries to resolve, the spell won't resolve and none of its effects will happen. You won't create a Rat token.