Winter Orb
Artifact
As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.
Illustrated by
Fourth Edition#358RareEnglishLegality
Rulings
Jun 8, 2016
All permanents untap during a player’s untap step at once. If Winter Orb is tapped as your untap step begins, your lands will all untap.
Jun 8, 2016
You can’t tap Winter Orb just because you want to. Another ability, such as that of Glare of Subdual, must instruct or allow you to do so.