Zay Kerik, Dark Guardian

Domain - Whenever a Black creature enters the battlefield under your control, put a -1/-1
counter on target creature.
{r/w}{r/w}{r/w}{r/w}{r/w}: Untap all attacking creatures, there
is an additional combat phase after this one.
Activate only if you control a creature named
Sarah Kerik, Light Guardian.
—
"Control your anger, but use it." -Kelik Koon