While talking to his cat (everyone does that, right?), malaphor follower Ian told him “You’re not the brightest toolbox in the shed.” As usual, I’m sure Ian’s cat looked at him like HE was the idiot. This is a triple congruent conflation of “not the sharpest tool in the shed”, “not the sharpest (or brightest) crayon in the box”, and “not the brightest bulb in the chandelier (or “not the brightest”), all meaning someone who is not very intelligent. Other similar idioms include “not the sharpest knife in the drawer”, “he’s one fry short of a Happy Meal”, “the elevator doesn’t go to the top floor”, and my personal favorite, “somewhere there’s a village missing its idiot”.
Finally, this malaphor is similar to my June 24, 2013 posting, “not the brightest tool in the shed”. https://malaphors.com/2013/06/24/not-the-brightest-tool-in-the-shed/ Thanks to Ian for sending this one in!