Kungamor, Bringer of decay

You may cast Kungamor From the Graveyard.
When Kungamor attacks or Leaves the battlefield
each player mills cards equal to the number
of creatures and lands in your graveyard.
For each opponent milled a creature and land
this way you, may return a creature and land
from your graveyard to hand.
Kungamor can only attack the player with the
most cards in their graveyard.
(if you have the most, or it is tied,
he cannot attack)