Megavolt, Electrical Savant

All artifact creatures in your hand gain Magnitude 3 (If you pay {3} when casting this spell, it can't countered or targeted of a spell or ability an opponent controls on the battlefield unless that player pays {3} or the effect is countered. Put 3 +1/+1 counters on it when it enters the battlefield.)
{r}, {t}: Put a +1/+1 counter on target artifact creature.