Ah ha! You have fallen into my elephant trap 😂. This is a long running gag/argument on Planet Rock. The cause of a moonbow is reflected light from the Sun, so it’s not actually dark, just nighttime. To create a rainbow, light needs to be refracted through water, dark is the absence of light. Semantics, I know, but good fun.
Speaking of Dio and his lyrics:
“Ride the tiger,
You can see his stripes but you know he's clean.
Oh, don't you see what I mean?”
No, Ronnie, I don’t .