Goku, Realm Protector

If damage would be dealt to Goku, Realm
Protector from a creature source, prevent that
damage and put that many +1/+1 counters on it.
{t}: Remove all +1/+1 counters from Goku,
Realm Protector. The next instant or sorcery
spell you cast this turn costs {x} less to cast,
where X is the number of +1/+1 counters
removed this way.