Stormweaver Apprentice

Whenever you cast a spell, put a chain lightning counter on Stormweaver Apprentice.

Whenever Stormweaver Apprentice attacks, you may remove any number of chain lightning counters from it. For each counter removed this way, Stormweaver Apprentice deals 1 damage to up to that many target creatures defending player controls. Each creature can't be targeted more than once this way.