Hundreds of high-pitched squeaks fill the air as a mass of small, carnivorous bats surges forth, all of them hungry for blood.
Bat swarms dwell in large caves, ruins, or even city sewers—anywhere they can find darkness to hide in during the day and a supply of food to feast upon at night. They are only encountered outside in a group at dawn or dusk, or when they have been startled and forced to flee their lairs.