As the black hole consumes these negative mass particles, it’s as if it is eating negative calories, resulting in its mass going down, not up. Viewed from the outside, the black hole thus appears to steadily shrink as it radiates particles. Were it not that the source of the radiation is exotic—a black hole immersed in the quantum bath of fluctuating particles inherent in empty space—the process would appear thoroughly pedestrian, like a glowing chunk of charcoal radiating photons as it slowly wastes away.
