Filamentous lightning that visibly spreads out beneath a storm's anvil canopy is known as anvil crawlers, or "spider lightning". Here, the latter moniker is more appropriate than usual, given the arachnid gemometry of the discharge. This electricity burst forth in quick shots downshear from a supercell that was being overtaken by a bow echo. Individual lightning tendrils spread much more abruptly than most anvil crawlers, but not quite as fleeting in character as anvil zits.
2 NE Apache OK (13 Apr 12) Looking N