Impending Disaster

{1}{R} · Enchantment

At the beginning of your upkeep, if there are seven or more lands on the battlefield, sacrifice this enchantment and destroy all lands.

Motor: se resuelve a mano

Rulings (3)

If this card is not on the battlefield at the times its ability resolves, then you can’t sacrifice it. However, you still destroy all lands.
Wizards of the Coast · 2010-06-15
The ability is not optional.
Wizards of the Coast · 2004-10-04
This ability does not trigger at all if there are not seven lands on the battlefield at the beginning of upkeep. It checks this number again when it is going to resolve and does not do anything if the land count is below 7.
Wizards of the Coast · 2004-10-04