When triggered by an object or a living being it instantly heats up to lethal temperatures approaching 1500K.
The anomaly remains stationary throughout its lifetime (a week on average). It can be visually detected in daylight by the air fluctuation above.
Usually the anomaly is roughly 10 meters in diameter, accumulating static electricity in vast quantities.
Strange chemical processes go non-stop in this anomaly...
They result in acid which eats away skin and toxic gas which devours lungs equally well...