Setiva, the Biollusionist

When Setiva enters the battlefield, Alter 3 (You
may add 3 time counters from any card in exile you
own, or remove 3 time counters from any card in
exile you don't own.)
Whenever Setiva alters, choose a card in exile.
Search your library for a card with equal mana
value and exile it with X time counters where X
is its mana value. Then, remove X time counters
from it where X is the number of counters you
have altered this turn.