Ever It Uncoils

Ever It Uncoils enters the battlefield with X
+1/+1 counters on it.
At any point during your turn, you may pay {x}{g}{g} and add X +1/+1 counters to Ever It
Uncoils. X cannot be more than 10.
Ever It Uncoils requires an additional creature to
block for every 10 power it has.