Many times though the book, references are made to Harold Lauder's favorite candy bar- the chocolate covered Payday candy bar. Many times through the course of the book, references are made to the path of chocolate covered Payday candy bars. In the biggest slipup of all, Stephen King leaves the clue of a chocolate thumbprint from a chocolate coated Payday in Stan's diary, allowing him to see that Harold was in there.
I find it kind of funny that, of all the candy bars that existed at the time of this book's writing, Stephen King chose a candy bar that contains NO chocolate WHATSOVER. Whoops!