Hidden Cataract (M3C-348) - Modern Horizons 3 Commander

Hidden Cataract enters tapped.
: Add .
, , Sacrifice Hidden Cataract: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)