Voodoo Initiate

Curse 1 (When target creature interacts with a
Curse-source, put X Curse counters on it.
If target creature has equal to or more Curse counters
than it has toughness, the opponent gains control of it
and it loses all Curse counters.
It is now a Black Zombie in addition to all other
creature types. Black Zombies can't have Curse
counters or be the target of Curse spells.)