Hungering Gaze

Each opponent chooses 1 land they control.
Tap those lands. For each land tapped in this
way, gain 1 mana of any colour that land could
produce. If that land could not produce mana,
or was already tapped, exile it instead.
Lands tapped in this way do not untap during
their controller's next untap step.
They looked on enviously from their wastes, at what
they could have had. They decided to take it - by force.