Nonexistent lands for opponent

Whenever an opponent taps a land for mana, tap all lands that player controls. If a creature an opponent controls attacks, all creatures that opponent controls attack if able.

As this enchantment enters, choose a land type. Each land of the chosen type has phasing. (It phases in or out before its controller untaps during each of their untap steps. While it's phased out, it's treated as though it doesn't exist.)