cr:5.3.2a

If the layer is a triggered-layer created by a triggered effect with a state-trigger condition, the state-trigger condition must be met by the current game state - otherwise, the layer fails to resolve.

Example: An attack with phantasm is defended by an attack action card with 6{p}. Before the phantasm triggered-layer effect resolves, the attacking hero plays Blinding Beam, giving the defending card -2{p}. When the phantasm triggered-layer resolves, the game state condition that caused phantasm to trigger is no longer true, therefore the phantasm triggered-layer fails to resolve and does not generate any effects.