Lava eels

Description
Lava eels are large, eel like creatures that exist deep inside of Atherton. Lava eels live in, as their name implies, lava. Lava eels lurk under the surface, rising swiftly upwards to eat swarms of Fire bugs. Lava eels are immune to Fire bug stings, and can thus eat them, controlling the population. Dr. Kincaid has stated that they may rise suddenly near humans, as they are attracted to the fire bugs, which are attracted to motion.

Appearance in books
In the 2nd book, Atherton: Rivers of Fire, lava eels are first encountered as the main group crosses a narrow pathway between pools of lava. Although the children are scared, Dr. Kincaid tells them that the Lava Eels are not particularly aggressive.

In the 3rd book, Atherton: The Dark Planet, Edgar finds lava eels in the first layer inside the Raven. When he is looking at the patterns of flies behind the glass, his is suprised when a lava eel rams into the glass. Later, he uses these to scare Red-eye and his brother socket when they board the raven with the green team to go to Atherton.