Thunder, Horse of Revenge

+2: Create 2 1/1 white and green Horse creature tokens.
-X: Create X 0/1 white Horse creature tokens then horse creatures you control get +X/+1 and gain trample until end of turn.
-10: You get an emblem that says "At the beginning of your upkeep create X 1/1 green Horse creature tokens where X is the number of Horses in play.