Exponential Overgrowth

Double the number of each type of counter
on target creature. As an additional cost to cast this spell you may pay
{g/u}{g/u}{g/u}{g/u}. If you do, double those counters
a second time. If you do, you may pay {g/u}{g/u}{g/u}{g/u}{g/u}{g/u}{g/u}{g/u} to double those
counters a third time.