Slaver of the An-Kuth

When this creature enters the battlefield, exile
target creature an opponent controls until this
creature leaves the battlefield.
This creature can'tattack or block if no creature
card is exiled this way.
{2}{b}: Target creature gets -X/-X where X is
the exiled creature power, then put exiled
creature on their owner's graveyard.
{2}{w}: Exile this creature, return it to the
battlefield under it's owner control.