Como coste adicional para lanzar este hechizo, puedes perjudicar 1. (Puedes poner un contador -1/-1 sobre una criatura que controlas.)
Destruye la criatura objetivo con valor de maná de 2 o menos. Si se pagó el coste adicional de este hechizo, ganas 2 vidas.
If a creature on the battlefield has
in its mana cost, X is 0 for the purpose of determining its mana value.
If the target creature is an illegal target as Requiting Hex tries to resolve, it won't resolve and none of its effects will happen. You won't gain life even if the additional cost was paid.