Devourer of the Deeps

This creature costs {1} less to cast for each card
type in all graveyards and the death zone.
At the beginning of your end step, each player
mills 2
This creature can block an additional 3 creatures
in combat.
After this creature deals combat damage, each
creature that was blocked by this creature with
a mana value less than or equal to the number
of card types in all graveyards and the death
zone phases out.