Staked for the Sirens

Enchant Creature
Enchanted Creature does not untap during its
controller's untap phase. It's controller cannot
activate an ability it has that causes damage.
Whenever a blue creature comes onto the
battlefield under your control, put a -1/-1
counter on the enchanted creature.
"Serfs kow Warlocks and fire are a bad mix, so they
ground a suspect in water, sometimes to his doom.