A humorous and deliberate miswording of "hell of a mess," meaning a very problematic situation that is extremely difficult to rectify, or a very large mess that will be tedious or time-consuming to clean up or organize. Welp, this sure is a mell of a hess you've landed us in this time—how are we going to get out of this one? Sarah and her friends left one mell of a hess in the living room after their slumber party.