Land of the dead

If you have 5 or more zombies under your control: All zombies have +1/+1
10 or more: All zombies have Deathtouch
20 or more: All zombies have +1/+1
100 or more: All zombies enter the battlefield under your control and you gain control of all zombies.
1000 or more: All zombies have haste and Unblockable
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You dont want to know what happens when they hit critical mass...