Spare Artificial Being

Modular 4
Megaconvert {4} (You may cast this card face down
as a colorless artifact with "{t}: Add {c} to your mana pool." for {3}. }. Turn it face up any time for its megaconvert cost and put a +1/+1 counter or a charge counter on it.)
When Self-Assembling Machine is turned face
up, you may put a +1/+1 counter on target artifact creature you control.