The worms are young click beetles, according to the entomologists' best guess. (Cramer also canvassed Reddit/Whatsthisbug, which seems to agree with the beetle ID.) Their next question: Why glow, little worm?
Through a process known as bioluminescence, animals can produce chemical light. They use this light to achieve a variety of goals: to ward off predators, to act as decoys and to communicate. Fireflies, for example, light up their posteriors to find mates.
Given that Cramer's worms had giant jaws (a sign of a meat-eating disposition), the entomologists believed the bugs' green glow might serve a similar purpose. To find out if the bugs were predatory, they offered up an ant to one of the worms. And, well, then this happened:
The worm's head peeks out of the center of the dirt, latching onto the ant. (Rainforest Expeditions/YouTube)
Entomologist Aaron Pomerantz explains the discovery in the video below: