Lumon

It inches along charged stems sipping the faint current that runs through Donar's lightning-fed vegetation, storing it as the soft light that suffuses its body. Its glow serves to keep the swarm together in the dark and to warn, faintly, that it tastes of stored charge, a mild but memorable deterrent. Utterly dependent on the group, a Lumon strays only far enough to feed, and clusters of them cling to the undersides of leaves through the night, a scatter of pale lights that pulse slowly in and out of unison like breathing.