The Antivitality

When the Antivitality enters the battlefield,
create a 1/1 black zombie creature token with
an antivitality counter on it.
Creatures with antivitality counters are zombies
in addition to their other types and deal damage
in the form of antivitality counters.
At the end of your upkeep, gain control of all
creatures with antivitality counters.