The caster utters a uick invocation to create a black nimbus around his/her hand, then hurls three rays at  one or more targets in range. The rays may be divided between targets however the caster likes. Make a ranged spell attack for each target (not each ray each ray that hit deals 1d10 points of cold damage. A target  that was hit by one or more rays must make a successful Constitution saving throw or be unable to use reactions  until the start of next turn.