Kamelot
"Poetry for the Poisoned, Pt. I: Incubus"

There was a time when I was young
A boy with bold ambitions
There was a time when I could tell
The crooked from the wicked one

There was a song that someone sung
A hint of recognition
There was a time
I knew you well enough
To know you won't be gone

Come with me tonight
Tell me how it feels to be alive

There was a time I had respect
A name of reputation
There was a time
When I could watch myself
Without being disgraced

Come with me tonight
Let us find a place where we can hide

Come into the light
Let me show you how we stay alive

(instrumental)

(spoken)
The word "incubus" means "to lie on",
and it was believed that any heavy feeling in bed,
such as a weight pressing down on your chest,
especially accompanied by nightmares,
was a sure sign that an incubus had attempted to have a nocturnal intercourse with you.
Given the religious fervor of the middle ages,
there's not all together surprising that the idea of a demon lover, was believed to account of this phenomenon