Magneto, Lord of Genosha

Flying, protection from blue
As long as Magneto, Lord of Genosha is
untapped, blue creatures opponents control
don't untap during their controllers' untap steps.
At the beginning of each opponents' untap steps,
that opponent may choose any number of tapped
blue creatures they control and pay {3} for each creature chosen this way. If the opponent does,
untap those creatures.
{1}{r},{t}: Tap or untap target artifact.