The Noonday Devil, daemonium meridianum, is traditionally used as a synonym for the sin acedia, especially considered an affliction of ascetics and hermit monks. It is a state of spiritual sloth, or rather hopelessness, ”the sorrow of the world that worketh death” according to Thomas Aquinas. Even though somebody in the present might be inclined to call it depression, theologians of the early church considered it a dangerous temptation.

If we look at the origin of the term, it appears in the Vulgata (Psalms 90:6, however, in most translations it is Psalm 91:6). The original Hebrew speaks of a ”destruction that despoils at midday”.

First one might think that acedia has nothing to do with the dramatic situation here, but the more I read about it, the better it seems to fit. Of course, the reader might prefer me to draw more comics instead of getting bogged down in Biblical exegesis…

He that dwelleth in the aid of the most High, shall abide under the protection of the God of Jacob.
He shall say to the Lord: Thou art my protector, and my refuge: my God, in him will I trust.
For he hath delivered me from the snare of the hunters: and from the sharp word.
He will overshadow thee with his shoulders: and under his wings thou shalt trust.
His truth shall compass thee with a shield: thou shalt not be afraid of the terror of the night.
Of the arrow that flieth in the day, of the business that walketh about in the dark:
of invasion, or of the noonday devil.

(Douay-Rheims Bible, Psalm 90:1-6. If you preter to read a more modern translation, there’s the New Living Translation and the New International Version.)