Lord Kroak

Flying, Ward {4}
Defender of the Great Plan- Whenever another
Dinosaur or Lizard enters the battlefield under
your control, exile the top X cards of your
library, where X is that creature's mana value.
You may cast an instant or sorcery from among
those cards with mana value X or less without
paying its mana cost. Put the rest of the cards
on the bottom of your library in any order.