Ugin, the Ineffable (M3C-160) - Modern Horizons 3 Commander

Colorless spells you cast cost less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.