Old textbook method of confusion

"The fact that 'devils' are predominantly comic figures in the modern imagination will help you. If any faint suspicion of your existence begins to arise in his mind, suggest to him a picture of something in red tights, and persuade him that since he cannot believe in that (it is an old textbook method of confusing them) he therefore cannot believe in you."

-- The Screwtape Letters by C. S. Lewis