Chimera Spawner

{2}{u}{b}{g}: Exile a creature card from your
graveyard with a Chimera counter on it.
Create a token that is a copy of that creature.
When you control 3 or more cards in exile with Chimera counters, remove those counters and sacrifice all tokens created by Chimera Spawner.
Create a Chimera creature token that has all abilities of the sacrificed creatures and with power
and toughness equal to the combined power and toughness of those creatures.