An anomaly of presumably gravitational nature. When triggered, the tremendous power of the "Vortex" drags everything within the radius of 10-15 yards into its center. Victims drawn into the core have no chance of survival: the bodies of animals and human beings alike are quickly constricted into a tight lump, only to be blown up a moment later in a powerful discharge of energy.
The anomaly remains stationary throughout its lifetime (a week on average). It can be visually detected in daylight by the air fluctuation above, dancing leaves, fragments of dismembered corpses lying around, and a distinctive dark stain in the center. Highly dangerous at night since it can be revealed only by means of a detector, or by throwing metal objects into it.