Noun
A coleopterous insect of the genus Lampyris; esp., the wingless females and larvae of the two European species (L. noctiluca, and L. splendidula), which emit light from some of the abdominal segments.
Source: Webster's dictionaryIn The Shadow of Kyoshi, it is revealed that incredibly powerful spirits are also capable of tearing physical rips between the realms that allow for direct transition, as Father Glowworm does. Source: Internet