Chaotic Lore

Cascade (When you cast this spell, exile cards from
the top of your library until you exile a nonland card
that costs less. You may cast it without paying its
mana cost. Put the exiled cards on the bottom in a
random order.)
Draw a card. If a card with mana value 4 or
greater was revealed with Chaotic Lore's cascade ability, discard a card at random.