Source: Dragon Annual 5
You change the effect of a ray spell to a 30-foot radius burst centered on yourself.
Benefit: A ray burst hits all targets (friend or foe) within 30 feet. Targets within 30 feet are allowed a Reflex save to avoid the burst. Any targets that do not avoid the effect are treated as if they were hit by the ray spell. Any target with 100% cover with respect to the caster is not affected. A ray burst spell uses up a spell slot three levels higher than the spell's actual level.