The Sentinel

Vigilance
The Sentinel enters the battlefield with five {e}
counters.
{x}{u}{b}{t}: X can be paid with energy counters.
Target artifact gets a number of +1/+1 counters equal
to the amount of {e} paid for X. If that artifact isn't a creature, it becomes a creature.
{e}{g}{w}{r}: Another target artifact gets +X/+X until
end of turn where X is The Sentinel's power.