This post will be brief but awesome.
Did you know that there are little insects that glow (like lightning bugs/fireflies) underground in caves?
Well, there are.
They use a chemical process called bioluminescense, just like lightning bugs do. See them? They are clustered - hundreds of them - along the ceiling of this cave over the water.
My imagination is spinning with possibilities...
Yes, there will be glow worms in my story.