Hastur, the Unspeakable

Vigilance
When Hastur, the Unspeakable enters the batthefield, tap all other nonland permanents. Nonland permanents do not untap during their controller's untap step. Hastur, the Unspeakable's power and toughness are both equal to the number of tapped permanents on the battlefield. Nonland permanents come into play tapped. At the beginning of your upkeep, you may tap Hastur, the Unspeakable. If you do not, you skip your next turn.