* ActorAllusion: [[Creator/JimCummings Cat]] often refers to Winslow as a "[[WesternAnimation/SonicSatAM blue rodent]]."
* AdoredByTheNetwork: It was at first, in the beginning, it was one of the few cable cartoons at the time to be given more than the standard 13-episodes per season, which even surprised creator Peter Hannan... ''however'', see ScrewedByTheNetwork below.
* DoItYourselfThemeTune: Peter Hannan wrote and recorded the theme song on a whim in his bedroom in the midst of pitching the show as a series of shorts. It turned out to be the show's biggest selling point when the people at Nick [[EarWorm couldn't get it out of their heads]] and, realizing they had a hit on their hands, expanded it to a full series. Hannan would later joke that now writes a song for every subsequent pitch he tries to sell.
* DreamTeam: Creator/JimCummings and Creator/TomKenny in the lead roles. As the former's character might say, it just doesn't get any better than that!
* KeepCirculatingTheTapes: [[https://www.youtube.com/watch?v=CTG6lbkEP_k The full version of the theme song]], with two additional verses and a harmonica solo. Nickelodeon aired it as a music video exactly once.
* TheOtherDarrin: Shriek's father was voiced by Creator/JimCummings in "Rich Shriek, Poor Shriek", but his cameo in "The Great Parent Mystery" had him voiced by Creator/BillyWest instead.
* ScrewedByTheNetwork: Nickelodeon, for whatever reason, decided to just up and pull the plug on the series while the final season was still in its initial run, and as a result, several episodes from the end of the final season were never aired on Nick; they were, however, lated seen when the show aired on the Nicktoons Network.
* ShortRunInPeru: The finale didn't air until 2005, after it had been shown in other countries.
* TalkingToHimself: Mervis and Dunglap were both voiced by John Kassir.
* TeasingCreator: Peter Hannan tends to give very roundabout answers to the infamous "bathroom" question. In the book "Not Just Cartoons: Nicktoons!" his explanation is that they simply don't... even though several episodes clearly indicate that they do.
** Peter Hannan originally pitched the idea as a series of two-minute shorts. Once he recorded the theme song, however, the Nick higher-ups decided to make it a series.
** Before it was pitched to Nick, [=CatDog=] began as an idea for a children's book about a two-headed superhero.
** The creators stated that the purpose of the show is to "really play off of kids' sympathies" by portraying the characters experiencing "the worst of the worlds."
** According to Peter Hannan, Mr. Sunshine is a "pig man."
** One of the crew members, Ray Pointer, was caricatured as a magician called "The Amazing Ray" in "[=CatDog=] Divided." He considered it an insult, and the character never appeared again.