Time Bound Beast

Flash, trample.
Time Bound Beast enters the battlefield with 1 time counter.
Whenever Time Bound Beast attacks or blocks, put a time counter on it.

When Time bound Beast leaves the battlefield, return its owners board to the state it was in at the beginning of their upkeep X turns ago, where X is equal to the number of time counters on Time Bound Beast.

"Would Tuesday be convenient for you?"