Herald of Halcyon Times

Nurture 4 (Tap any number of
creatures you control with total power 4 or
more: put a level counter on this creature.
Nurture only as a sorcery).
Level 1-3: 2/3, Creature tokens you control
gain +1/+1.
Level 4+: 3/4, Other creatures you control gain
+1/+1.