The Moment

At the beginning of your upkeep, put a time counter
on The Moment.
{2}, {t}: Untap target creature you control. It phases
out until The Moment leaves the battlefield.
{3}, {t}: Destroy each nonland permanent with
mana value less than or equal to the number
of time counters on The Moment. Then
sacrifice The Moment. Activate only as a sorcery.