Spoka, Possessed Oathspeaker

When Spoka, Possessed Oathspeaker deals
combat damage to a player, that player can't
speak until their next draw step.
If that player would speak for any reason
before their next draw step, exile the top card
of their library. You may cast any card exiled
this way without paying its mana cost.
"To be mute is to be wise."
-Gin, the Forbidden