Infinite land/mill

(This land isn't a spell, it's affected by summoning sickness, and it has ": Add .")

Creatures don't untap during their controllers' untap steps. Whenever a creature enters, untap all creatures.

Enchant creature Enchanted creature has ": Create a token that's a copy of this creature, except it has haste. Exile that token at the beginning of the next end step."

Target player mills X cards, where X is the number of lands you control.