The Millennium Calendar [The Lost Caverns of Ixalan Prerelease Cards]

Whenever you untap one or more permanents during your untap step, put that many time counters on The Millennium Calendar.

2, T: Double the number of time counters on The Millennium Calendar.

When there are 1,000 or more time counters on The Millennium Calendar, sacrifice it and each opponent loses 1,000 life.