Ynmann's Eternal

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast an instant or sorcery spell,
you may have Ynmann's Eternal deal 1 damage to target planeswalker. If you target a planeswalker
you control this way, its dealt damage in the form
of loyalty counters.