Spectral Rebel

Bestow {3}{w}{w} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Defiant (Whenever this creature attacks, if defending player controls an untapped creature with power greater than this creature's toughness, put a +1/+1 counter on this creature.)
Enchanted creature gets +1/+3 and has defiant