(Strip Number 1052, Original Publication Date, 14 May 1986)
Panel 1: As Lizzie plays in the mud, Mike's silhouette approaches from the distance.
Panel 2: He materializes on the scene to remind her that she's getting her good clothes all dirty.
Panel 3: He then warns her that she should take them off if she wants to avoid trouble.
Panel 4: Since Lynn has a warped fixation with naked pre-schoolers, Lizzie doesn't realize Mike said change into play clothes and thus continues merrily on bare the Hell naked.
Summary: Lizzie's being all nakers allows Lynn to tick off the boxes "freak people out by having the kids run around in the buff" and "have a parent freak out because their kids defy Mom and her sidekick God by running around in the nude" on her Big List Of Irritating Punchlines.