Cernos the Returned

When Cernos the Returned enters the battlefield,
tap all other creatures.
As long as Cernos the Returned is on the
battlefield, they don't untap during their owner's
untap step.
When another creature enters the battlefield,
tap it. As long as Cernos the Returned is on
the battlefield, they don't untap during their
owner's untap step.