Improbable Combo:
Have Wild Pair out. You have at least 6 mana.
Cast Master Biomancer (P/T = 2/3), pair with another Master Biomancer (P/T = 2/3, but gets 2 counters from the other Biomancer).
Cast Sage of Hours (P/T = 1/1, but gets 6 counters from the Biomancers), pair with Novablast Wurm (P/T = 7/7, but gets 6 counters from the Biomancers).

Take an extra turn. Destroy all other creatures and attack with your 13/13.