Glow worms are worms that usually live in caves. They have a type of bacteria that "glows". That allows their behind to glow. A glow worm uses its "glow" to catch insects.
Hunting
Glow worms make something like a spider web made of mucus. They climb to the top of the cave and just let down several strings of mucus. At the tip of each one, it places some bacteria that glows. Then, it climbs into a "bed" made of mucus and waits. The caves insects, being attracted to the blueish glow, fly to it and get stuck into the slimy mucus. The glow worm "reels" in its prey and devours it.