!!If you're looking for examples related to a specific show or movie, see these:
!![[Film/ScoobyDoo The 2002 Film]]
* The plot of the entire film is pretty horrifying. There are a bunch of ancient demons running around trying to take over the world by possessing humans (including Mystery Inc.) and being led by a vengeful sociopath.
* The first scene with the Luna Ghost is can be pretty jarring. Not only is the monster pretty freaky, the scene in general is kind of intense. And Daph is all of a sudden the bait to top it all off.
* Spooky Island in general is pretty... eerie. There's the symbols everywhere that are based off the demons and the whole place just has a sense of dread. It's like a Halloween-based theme park that completely forgot everything was supposed to be fake.
* ''WesternAnimation/TheScoobyDooProject'' [[http://www.youtube.com/watch?v=uMsA6_Qh_jw  ]]. It's a parody of ''Film/TheBlairWitchProject''. That should show give you a good idea. [[spoiler:What makes it worse is it's implied the gang ''died'' at the end]].
* One classic ad on Creator/CartoonNetwork featured characters from WesternAnimation/ScoobyDoo: Shaggy showed up in a spooky castle calling out, "Scooby-Doo! Where are you?" This cut to Scooby on a tropical beach, saying, "Right here, Raggy! On Rartoon Network!" What was scary about it was not only the notion that Scooby would desert his friends in the middle of a case, but also the fact that Shaggy was barely animated at all, paralyzed and semi-slouched in seeming defeat as he called for help. It was ''haunting.''
* The townsfolk (plus Daphne) turning into werewolves in the first episode of ''WesternAnimation/TheThirteenGhostsOfScoobyDoo''.
* The Ghouls getting [[BrainwashedAndCrazy Revoltized]] in ''WesternAnimation/ScoobyDooAndTheGhoulSchool'', specifically their expressions: Sibella's eyes [[WideEyesAndShrunkenIrises shrink as if she were going feral]], Elsa looks like her mind just got fried, Phantasm quickly loses her GenkiGirl composure and scowls for the first time in the whole movie and Winnie howls for some indiscernible reason. Elsa, Winnie and Tanis were freed early, but Sibella and Phanty remained under the spell longer. The former was freed by Tanis and apparently needed a few seconds to shake off the effect. Phanty, being under the longest, probably would've had more permanent effects had Scooby not knocked over random chemicals in the potion.
--> '''Tanis:''' Gee... you were under the hairdryer so long, you were getting cranky.
* In one of ''The New Scooby-Doo Movies'' episodes, the gang helped Creator/DickVanDyke discover that his circus was being terrorized by the strongman, sneaking up on the guy while he's working out. But the strongman reveals that he not only heard them, and demonstrates what he'll do to them by effortlessly twisting his barbel like a pretzel. This is not the usual greedy Scooby villain; this guy intends to straight up ''murder'' the gang.