- Actor Allusion:
- Casey Kasem, the previous voice of Shaggy, provides the voice of his father, Colton Rogers.
- Matthew Lillard, who played Shaggy in the live action theatrical films, voices Shaggy starting with this series, replacing Casey Kasem.
- James Marsters playing an American character who uses a British accent.
- Clancy Brown once again voices the supernatural villain of a series, who has been manipulating the evil genius big bad to follow his will.
- This isn't the first time Patrick Warburton has played a lawman or a character with the last name Stone.
- In Episode 4, David Faustino plays a down-on-his-luck guy named Bud. Huh, where have we seen that one before?
- The mother of Velma's Stalker With a Crush Jason is played by Jessica Walter, who played one herself in Play Misty for Me.
- In episode 18, James Hong's character takes on the guise of a powerful Chinese wizard.
- Of course, the H.P. Lovecraft Expy is played by Jeffrey Combs.
- From "The Night the Clown Cried", Crybaby Clown is voiced by Mark Hamill, who has much experience with voicing clowns.
- Crybaby Clown also seems like an allusion to Hamill's role as Macendale/Hobgoblin on Spider-Man: The Animated Series, since the villain is more practical-minded than Joker, and both are shallow pretty-boys who romance the local rich girl who is fed up with her distracted ex/potential beau and turn to destructive crime waves in the name of money/fame. Both Daphne and Felicia Hardy are made to feel like fools when their date is unmasked.
- His alter-ego is voiced by his father, Matt Lanter.
- Early on in season two, Velma seems to have become pretty good friends with Hot Dog Water. It probably doesn't hurt Hot Dog Water's voice actress Linda Cardellini has a bit of a past relationship with Velma...
- Ricky Owens's teenage voice actor was Scott Menville who played Shaggy in Shaggy & Scooby-Doo Get a Clue!
- Horatio Kharon, the dancing man in Scooby's dreams, is played by Michael J. Anderson, who played "The Man From Another Place" in another show that takes place in a small town. The characters are also rather functional and similar in design and role, down to looking almost exactly like the actor.
- In Episode 12, Harlan Ellison spouts out a paragraph about the monster, full of "f" words (but not the F Word).
- Tim Matheson is basically voicing an adult version of Jonny Quest, to the point where the character in season two is radically redesigned from his teenage self to resemble Jonny.
- Gary Cole becoming Fred's adopted father isn't the first time he's taken a job from Tim Matheson. He also became Vice President in The West Wing after Matheson's character John Hoynes had to resign in disgrace.
- For the Freak of Crystal Cove, Frank Welker uses the voice he used for the Boogieman. Whether by design or coincidence, the Freak has a few visual similarities to Boogie (such as being pale white and having horns).
- Maurice LaMarche's voice for Vincent Van Ghoul sounds like a higher-pitched version of his Brain voice, which of course is a combination of Orson Welles and Vincent Price, the latter of whom Van Ghoul is based off of.
- The Cast Showoff: Daphne gets to sing, not one, but TWO songs in the episode "In Fear Of The Phantom". Grey DeLisle knocks both right out of the park.
- Casting Gag:
- Scott Menville voiced Shaggy in Shaggy & Scooby-Doo Get a Clue!. Now he's voicing Shaggy's counterpart in the predecessor Mystery Inc., albeit the teenage version
- Baylor is a trifecta:
- First, Matt Lanter played the Edward Cullen Expy in a Twilight parody, so having him play a parody of a Twilight actor seems fitting.
- Second, Mark Hamill plays a clown when his best known voice acting role was a clown.
- Finally, Matt Lanter voiced Anakin Skywalker at one point. Mark Hamill was of course, Luke. This means Crybaby Clown is his own father.
- Hot Dog Water, a knockoff of Velma, is voiced by the actress who played her in the live-action movies, Linda Cardellini.
- Shaggy's dad, Colton Rogers, is voiced by Casey Kasem, his very first voice actor.
- Descended Creator:
- Producer Mitch Watson voices Gary's friend Ethan.
- Paul Rugg voiced a professor character in an episode he wrote.
- Doing It for the Art: The reason Baylor Hotner initially became Crybaby Clown, to do research for his next film.
- Fandom Nod: In "Dance Of The Undead", when asked why the Hex Girls went back to their original outfits (resembling the ones worn in Witch's Ghost), they say that fans just preferred their original look. Some fans complained about their new look, so this is more than likely a little in-joke.
- Fan Nickname: The Nibiru Entity is actually referred to as The Evil Entity in the series proper.
- Jossed: Many people liked to believe that Cassidy survived the underwater explosion, and that she was just hiding. This is not the case, as she does not reappear until the timeline had been reset.
- Name's the Same
- Fred Jones Sr. is often referred to as Mayor Jones.
- Scooby-Doo meets Scooby the Seal.
- Non-Singing Voice: Averted with the Hex Girls and Daphne. All of the actresses performed the songs played within the show.
- The Other Darrin:
- Casey Kasem retired from the role of Shaggy, and handed the role over to Matthew Lillard. This is also a role reprisal from the theatrical live action films.
- Lewis Black voices Mr. E, but one episode has him voiced by Jeff Bennett.
- Due to Vincent Price's death, Maurice La Marche voices Vincent Van Ghoul.
- Gary, Ethan's friend, was voiced by Tony Cervone in season 1 and by Jeff Bennett in season 2.
- Screwed by the Network: Despite universal praise the series was screwed in Season 2 where there would often be months between new episodes and no news of when new episodes would come out. It was easier to find the episodes online rather than TV. Luckily however, they managed to wrap up the series at the end instead of outright canceling it like many other shows that have been screwed.
- Series Hiatus: Has had three. The series has now ended.
- Talking to Himself: Frank Welker voices Fred, Daphne's father and Scooby Doo.
- What Could Have Been: The final show was always meant to be a two-season series, but Word of God says that they actually did consider a Season 3
, which would have had a new Myth Arc and expanded on the Stealth Prequel aspect.
