Covetous Demon

Devour 2 (As this creature comes into play,
you may sacrifice any number of creatures. This
permanent enters the battlefield with 2 +1/+1
counters on it for each creature sacrificed
this way.)
Whenever Covetous Demon becomes blocked
by a creature, you may pay {2}{b/g}{b/g}: if you
do, that creature looses all counters, and abilities,
and becomes a base power and toughness 4/4
until end of turn.