Arguably, a selection of the worst prose written cannot but include the inimitable G Ragsdale McClintock, a delightful creation of Mark Twain. Twain writes of McClintock's work The Enemy Conquered; or, Love Triumphant:

The reader must not imagine that he is to find in it wisdom, brilliancy, fertility of invention, ingenuity of construction, excellence of form, purity of style, perfection of imagery, truth to nature, clearness of statement, humanly possible situations, humanly possible people, fluent narrative, connected sequence of events–or philosophy, or logic, or sense.  No; the rich, deep, beguiling charm of the book lies in the total and miraculous absence from it of all these qualities–a charm which is completed and perfected by the evident fact that the author, whose naive innocence easily and surely wins our regard, and almost our worship, does not know that they are absent, does not even suspect that they are absent.

 For example?

Her heart yielded to no feeling but the love of Elfonzo, on whom she gazed with intense delight, and to whom she felt herself more closely bound, because he sought the hand of no other. Elfonzo was roused from his apparent reverie.  His books no longer were his inseparable companions–his thoughts arrayed themselves to encourage him to the field of victory.  He endeavored to speak to his supposed Ambulinia, but his speech appeared not in words. No, his effort was a stream of fire, that kindled his soul into a flame of admiration, and carried his senses away captive. Ambulinia had disappeared, to make him more mindful of his duty. As she walked speedily away through the piny woods, she calmly echoed: "O!  Elfonzo, thou wilt now look from thy sunbeams.  Thou shalt now walk in a new path–perhaps thy way leads through darkness; but fear not, the stars foretell happiness."

Although it would be a pleasure to continue the quotation of Twain's A Cure for the Blues, which is well worth reading, let me exhort you to read this gem of a work; as Twain writes:

There is but one Homer, there is but one Shakespeare, there is but one McClintock–and his immortal book is before you.  Homer could not have written this book, Shakespeare could not have written it, I could not have done it myself.  There is nothing just like it in the literature of any country or of any epoch.  It stands alone; it is monumental.  It adds G. Ragsdale McClintock's to the sum of the republic's imperishable names.