Aradia Megido, Unbound

Whenever one or more other permanents
phase out and whenever one or more other cards are put into exile from anywhere, put a time counter on Aradia Megido, Unbound.
Whenever Aradia Megido, Unbound attacks, it deals damage equal to the number
of time counters on it to any target. If a creature dealt damage this way would die this turn, exile it instead.