idiom. This refers to the dumbest of the dumbasses, the munchiest of the buttmunches, and the assiest of the assbutts.
Real citation: "Yes, I know what you're thinking: "Tell me something else I don't already know."
But some things can't be reiterated enough.
Such as: Michael Medved is an idiot. He has a wet sock for brain. A thumbless grasp of the issues and a propensity for lachrymose whimpering when he doesn't get his way."
(James Wolcott, "Michael Medved Is an Idiot," Feb. 17, 2005, http://jameswolcott.com/archives/2005/02/michael_medved.php)
Made-up citation: “As the Bible says, ‘I’d rather have a wet sock for a brain than a wet thong for a heart.’”