A glowworm is a type of insect larva or wingless female beetle that produces a cold, greenish light from its body. Despite the name, glowworms aren't actually worms at all: they're young beetles or specialized adult beetles that never develop wings.

The glow comes from a chemical reaction inside the glowworm's body, called bioluminescence. The insect mixes special chemicals together to create light without heat, like a natural glow stick. Glowworms use this eerie light to attract prey or mates. In caves in New Zealand, thousands of glowworms hang from the ceiling like tiny stars, creating a magical underground sky that attracts tourists from around the world.

The most famous glowworm in North America is actually the larva of a different insect: the firefly. These glowworm larvae crawl through leaf litter and rotting wood, hunting for snails and slugs. After spending up to two years as glowing larvae, they transform into the familiar fireflies that flash on summer evenings.

The word glowworm perfectly captures what makes these creatures so remarkable: they're small, humble creatures that can literally light up the darkness around them.