spider lightning

Noun

 * 1) Very long flashes of lightning (tens or sometimes hundreds of kilometers long) that travel horizontally across the sky, tapping extensive pools of electrical charge in the clouds, particular once a CG (cloud-to-ground) channel is established.
 * 2) * 2019 August 22, Maya Wei-Haas, "Record-breaking lightning as long as Kansas spotted", in National Geographic:
 * One evening while working, Michael Peterson found himself staring at an enormous spider. But Peterson, a remote sensing scientist at Los Alamos National Laboratory, wasn’t looking at a critter of the eight-legged variety. Instead the form crawling across his screen was a monstrous flash of so-called spider lightning—a twisting network of light stretching hundreds of miles across stormy skies. The events highlighted in this latest study are what’s known as spider lightning. While you may envision lightning as largely vertical, spider lightning races horizontally through the clouds.

CAT:en:Lightning