Succubus Nightstalker

Flying, lifelink, menace
Phasing (This phases in or out before you untap
during each of your untap steps. While it's phased out,
it's treated as though it doesn't exist.)
When Succubus Nightstalker is phased in,
Humans get +2/-2, and Zombies get +1/+2.
"The souls of the living make wonderful food for the
bodies of the dead."