Charm of the Omen

Suspend 3 — {x}{b} (Rather than cast this card
from your hand, you may pay {x}{b} and exile it with
5 time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, cast
it without paying its mana cost.
Creatures you don't control have -0/-X.
at the beginning of your end step, if you control
10 or more cards in exile with time counters on
them, you win the game.