Revolvingdore

When a creature your opponent controls
becomes tapped, you may choose to untap Revolvingdore.
When a creature your opponent controls untaps,
you may choose to tap Revolvingdore.
When Revolvingdore becomes tapped, your
opponent may choose to untap a creature
they control.
When Revolvingdore becomes untapped, your opponent may choose to tap a creature
they control.