Coram & Big Kitty

This creature gets +X/+0, where X is the greatest
power among creature cards in all graveyards.
Whenever this creature attacks, each player mills a
card.
During each of your turns, you may play a land
and cast a spell from among cards in graveyards
that were put there from libraries this turn.
[[Petting a kitty this big may take a long time, but it
is worth it.]]