"Peeping Mom" is the eighteenth episode of Season 26.
Bart gives false information about his participation in a bulldozer crash, so Marge plans to pursue Bart everywhere until he tells the truth. Meanwhile, Homer ignores Santa's Little Helper when Flanders gets a new dog.
Returning home with Maggie from errands, Marge discovers that a part of Springfield is now totally destroyed. As Chief Wiggum announces that Bart could be the culprit, Bart says that he wasn't implied at all in the incident. This prompts Marge to follow Bart everywhere until he confesses.
However, Bart seems not to know what Marge is talking about. Marge eventually is fed-up and gives up her plan. It's then revealed that Bart was really culprit and he plans to create a new incident, but his conscience eventually wins and he finally admits his fault.
Chief Wiggum then arrests Bart but allows him to give a hug to Marge. Meanwhile, Homer learns that Flanders got a new female puppy dog named Baz. Though Homer isn't her owner, he eventually bonds with this dog, ignoring Santa's Little Helper. This saddens Flanders and he chooses to give the dog to his neighbor, much to his and his son's chagrin. However, Homer advises him to keep it since he will be a better owner than him, who in Baz's eyes, is just an another dog with whom she can play.
The episode finishes with Santa Little's Helper and Baz preparing to fight in a Far West Style.