The Space Trilogy/YMMV


 * Complete Monster: The Un-man, aka the Bent One and Satan. It is a being so evil that even to look at its face can cause an unprepared human to pass out, and while it is a highly intelligent tempter with solar system spanning plans, it derives at least as much pleasure from torturing animal life to death.
 * Nightmare Fuel:
 * The battle with the Unman and the Crapsack World speech by Weston in Perelandra.
 * The detailed description of the head and the creepy paintings in That Hideous Strength.
 * Seinfeld Is Unfunny: At the time the trilogy was first published, most aliens in SF stories were hostile savages intent on destroying humanity. For Lewis's aliens to be morally superior to man was a radical departure... which, of course, was widely adopted by later writers, somewhat diluting its impact today.
 * Of course, though, the thing that remains the most original with Lewis' premise is that nearly any other time aliens are morally superior, they tend to not believe in any Deity.
 * Values Dissonance: You're in a theological debate. You find yourself losing the argument and fear that your audience might be swayed towards the opinions of your opponent. What do you do?
 * Ransom himself thought that particular solution seemed crass, until he realized that his opponent was playing similarly dirty. The Un-man was using manipulative rhetoric to make his point, and was abusing the fact that he didn't need to sleep in order to physically wear down his opposition.
 * It could also be considered Values Resonance. After all, if you found out Satan was trying to make another Eden a Crapsack World/ Crap Saccharine World like ours, wouldn't you feel obligated to beat the ever-loving shit out of him?
 * You must also take into account that A) Ransom's opponent was literally Satan. There was no possible meeting of the minds or compromise here. It was victory and life or defeat and death (of an entire world). And B) This was not his first solution, but his last. He came to this conclusion only after being dragged through weeks of argument. It also required tremendous courage. Ransom fully expected to die, as he was a mortal entering physical combat with a demon.