WoWDB

You summon a flurry of stars from the sky on all targets within 40 yards of the caster that you're in combat with, each dealing [ 577 + 33% of Spell Power ] Arcane damage. Maximum 20 stars. Lasts 10 sec.

Shapeshifting into an animal form or mounting cancels the effect. Any effect which causes you to lose control of your character will suppress the Starfall effect.