Li Shen, the Silent Voice

Vigilance
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Li Shen, the Silent Voice attacks, you
may pay {2}{w}. If you do, create a white Aura
enchantment token named Bound in Silence with
enchant creature and "Enchanted creature can't
attack or block." attached to target creature
defending player controls.