Phantasmal Asphixiation

Your target must succeed at a Will save or believe it can no longer breathe. An affected target must attempt a Fortitude save each round at the beginning of its turn. The first time it fails the Fortitude save, it is staggered until the next time it attempts a save against the spell. If the target fails a second Fortitude save in a row, it falls unconscious for the spell’s remaining duration. The target breathes normally while unconscious, but is shaken for 1 minute upon awakening. If the target succeeds at two Fortitude saves in a row, it shakes off the spell’s effects entirely. Otherwise, the target continues to attempt a save each round until it falls unconscious or the spell ends. This spell has no effect on creatures that don’t need to breathe.