Kirkgard, Water Tyrant

When Kirkgard, Water Tyrant enters, target
opponent mills 4 cards.
Whenever you cast a sorcery or enchantment, target opponent mills cards equal to the cast card's
converted mana cost.
Whenever an opponent mills one or more cards, you
may cast cards with converted mana cost less than
the total number of cards milled without paying
their mana cost. This ability only triggers twice each
turn.