Omnath, Locus of Potential

Whenever you cast a spell with a mana value
greater than the number of growth counters on
Omnath, Locus of Potential, put a growth
counter on Omnath, Locus of Potential.
Omnath, Locus of Potential gets +1/+1 for each
growth counter on it.
{t}: Add X {c}, where X is the number of growth
counters on Omnath.