Crearo, Galaxy Creator

+3: Create a 5/5 Centaur creature token with, "Whenever you put a creature card from your hand on the battlefield, put a +2/+2 counter on this card."
-1: Search your library for up to 5 creature cards and put them on the battlefield with haste and a +1/+1 counter on it.
-7: Create an emblem with, "Whenever a player casts a card, you gain 5 life and each opponent loses 5 life."