As these creatures are mentioned only fleetingly, it is impossible to say if they were related to the great Worms (wingless Dragons), or if they were giant versions of regular glowworms. One can assume that they glowed in the dark (and therefore perhaps were related to, or were another name for, the spark-dragons).
Portrayal in adaptations
- Glow-worm is a monster found in the Dark Delvings of Moria and in The Hall of Lights in Mirkwood, portrayed as a giant glowworm and classified as "Spiders and Insects Crawler".
- J.R.R. Tolkien, Christopher Tolkien (ed.), The Book of Lost Tales Part One, "I. The Cottage of Lost Play", p. 18
- Deed: Glow-worm Slayer at The Lord of the Rings Online Community, accessed 23 October 2010
- Bestiary: Glow-worm Matriarch at ZAM, accessed 23 October 2010
- Monster: Glow-worm at The Lord of the Rings Online Community, accessed 23 October 2010