NotAllowedToGrowUp: The show really brings the Fridge Logic with this one. Throughout most of the series, the kids were in kindergarten, but they were finally allowed to advance to the first grade in the DVD release ''Back to School with Franklin'', which came after the fifth season. [[MST3KMantra Best not to think about this at all]] when it comes to either Bear's little sister Beatrice or Franklin's little sister, Harriet. In the first season, Bear's sister was born, but a couple seasons later, he said that she was four years old. And Franklin's little sister wasn't born (yes, born, not hatched) until after the fourth season in the film ''Franklin and the Green Knight: The Movie''. Yet by the next film, ''Franklin's Magic Christmas'', she was already talking and walking and by the time of ''Back to School with Franklin'', her speech had advanced and she was said to be just a year away from being able to attend preschool. In the sixth season, she became even more advanced.
* FridgeBrilliance: In "Franklin's Not-So-Broken Bone," Skunk is unable to go swimming with her friends because of her cast, but in "Franklin's Swimming Party," it's revealed that she can't swim at all. Could be fridge brilliance, though, if you consider that having the cast was a ready-made reason to decline the invite without revealing her secret.