Yellow Footprints

At the beginning of your end step, put a 0/1
green Recruit creature token onto the battlefield
with three training counters on it. That creature
has "At the beginning of your upkeep, remove a
training counter from this Recruit. Then, if this
recruit has no training counters on it, sacrifice it
and put a 2/2 green Junior Marine creature token
onto the battlefield. It gains haste until end of
turn."