Kirby krackle (sometimes Kirby dots) are an artistic convention in superhero and science fiction comic books and similar illustrations: a field of black, pseudo-fractal images are used to represent negative space around unspecified kinds of energy. They are typically found in illustrations of explosions, the blasts from ray guns, and outer-space phenomena.
Kirby krackle is a comic book visual effect named after Jack Kirby, the influential comic-book artist whose superhero art frequently featured it. The effect was developed from the use of a pattern of round black spots to depict smoke, energy, or flying debris from explosions, or as a way to manually generate the random patterns that depict the path of lightning and other energetic strikes.