Mik Davies was the author of the Underpants Bandits series, about 2 boys stealing historical undergarments.
He is mentioned in Diary of a Wimpy Kid: The Long Haul when Greg is given an assignment to pick an author to write about. All of Greg's classmates, especially the boys chose him to write to, but the teacher Mrs. Terry made them pick someone else. On the eighteenth of August, Greg wrote to him saying "I'm just writing to tell you, don't listen to these people who say your books are garbage, because they don't know what they're talking about. I know a bunch of kids (including me) who think your books are great. As far as the "rude humor" goes, I find that stuff hilarious, so please don't change a thing. In fact, I would encourage you to put MORE bodily functions and things of that nature in your books. Sincerely, Greg Heffley. About two hundred days later, Mik wrote back saying "Dear friend, Unfortunately I get so much fan mail that I'm not able to answer your letter personally. But I did want to tell you to be on the lookout for "Underpants Bandits 24: Lincoln's Longjohn's", coming soon to stores near you! Lots of yuks, Mik."
- All the boys who wanted to write to him would have been Greg, Rowley Jefferson, Chirag Gupta, Lionel James, James, Chris Hosey, Erick Bickford, Bryce Anderson, Ronnie McCoy, Alex Aruda, Collin Lee, Jamar Law, Fregley, Albert Sandy, Archie Kelly, Aric Holbert, Dwight Harrington, Ed Norwell, Edward Mealey, George Fleer, Christopher Brownfield, Christopher Ziegel, Tyson Sanders, Bryan Buttsy, Carl Dumas, Corey Lamb, Peter Lynn, Cody Johnson, Marty Porter, Martin Ford, Michael Sampson, Peter Uteger, Evan Pittman, Grayden Bundy, Jake McGough, Rodney James and Carlos Escalera.
- He is possibly based from real-life Captain Underpants author Dav Pilkey.