It is certainly not the best example of comic book storytelling, but Mickey Mouse in the Haunted Castle, published in Dell Four Color Comics #325, has merit enough to be featured here as part of a special Saint Patrick's Day-themed Four Color Friday.
Mickey and Goofy travel to Ireland to claim a radio contest prize, which to their amazement happens to be a "genuine haunted Irish castle." The castle in fact is not haunted by ghosts, but instead by a mischievous leprechaun. The story is a bit of a disjointed mess, both a mystery and treasure hunt mixed heavily with broad pratfalls and numerous irrelevant comedic sidesteps. In the end it is simple, silly fun, but distinctly lacking the talent and sophistication that a Barks or Gottfredson would bring to the page. Script credit for the story has never been determined.
Redeeming the overall effort is wonderful artwork by Al Hubbard. His renderings very much complement the whimsical nature of the story, and his design of the leprechaun character is especially well realized. Hubbard also treats readers to a few quite nice half-page splash panels that showcase the haunted castle of the story's title. Hubbard did not do the cover of the issue; the Grand Comics Database speculates that those pencils may have been the work of Carl Buettner.