Parasitic Butterfly

Flying, Chestburst(When you play this spell,
you can remove all Egg Counters from one
target creature; each counter removed reduces
this card's cost by {1}, and deal damage to the
creature equal to the number of counters removed.)
{1}{b}{b}:Place an Egg Counter on target creature.
{g}{g}{t}:Remove all Egg Counters from target
creature. Deal X damage to it, and create X 1/1
insect creature tokens, where X is the
number of tokens removed.