History NightmareFuel / ScoobyDooOnZombieIsland

** While Simone and Lena being EvilAllAlong is hinted at throughout the film, the sudden revelation of what Mystery Inc. has gotten into is terrifying all on its own. They thought they were investigating more of their usual brand: things like people pretending to be zombies and using special effects... but what they got was a nightmarish human-trafficking scam run by [[SerialKiller demonic feline serial killers]] [[AndIMustScream that trap countless victims in a hellish limbo over the centuries]], along with said victims being desperate to scare away everyone before they suffer the same fate as them.

** The song itself can invoke this. It's a callback to the classic cartoon, which sometimes had songs play during scenes where the gang was being chased by the MonsterOfTheWeek. We even have a light rock version in "The Ghost is Here" (also by Skycycle) where the gang has the "investigating hauntings caused by people wearing masks" before meeting Lena. However, the songs in question were [[LighterAndSofter pop songs with soft vocals and light instruments]]. This time? We've got hard electric guitars, drums and loud vocals. Even the music isn't playing around.

*** Right before he transforms, he tells Shaggy and Scooby (who are overjoyed to have finally run into a friendly face after having been chased all over the island for probably hours) "I'm happy to see y'all!" Creator/JimCummings manages to make the line sound [[HeCanReallyAct both reassuring and terrifying]].

-->'''Daphne:''' This is more haunted stuff than I really want it!

''WesternAnimation/ScoobyDooOnZombieIsland'' is widely known for being the first (if not only) installment of the ''Franchise/ScoobyDoo'' franchise to be legitimately scary. This time, the monsters ''don't'' have a mask on; the terror is all very real. While plenty of the later DirectToVideo movies continued the DarkerAndEdgier aesthetic, few can hold a candle to the one that started it all. The movie's tagline sums it up nicely: "''This time, '''the monsters are real.'''''"

''WesternAnimation/ScoobyDooOnZombieIsland'' is widely known for being the first (if not only) installment of the ''Franchise/ScoobyDoo'' franchise to be legitimately scary. While plenty of the later DirectToVideo movies continued the DarkerAndEdgier aesthetic, few can hold a candle to the one that started it all. The movie's tagline sums it up nicely: "''This time, '''the monsters are real.'''''"

* Just before the deadline runs out, the werecats have finally cornered the gang, the zombies all defeated, and are closing in for the kill. Even when Beau tries to fend them off with a torch, Jacques is brave and strong enough to swat it away. The way the three ''stop'' speaking English and just ominously grow as they close in, no smirk, no taunts, without any change in their expressions, is terrifying. In this moment, all of their humanity was gone and they were just predators ready for their kill.

* [[FamilyUnfriendlyDeath Their deaths too]]. The moment they miss the deadline, their bodies begin sizzling and frying, and we see them howl, snarl, and screech in agony. They look up at the moon and are seemingly able to process that they missed their chance and are now going to pay with their lives before they really begin burning to death. We get to see the flesh vanish from their bodies until they’re left emaciated husks and then watch the fur be fried off of the skeletons, which then crumble to dust. They are completely aware and still alive throughout it, until the fur begins burning off their bodies and their eyes disappear from their skulls as they finally die; all that’s left is Simone’s necklace and scraps of their clothing. [[AssholeVictim Even so, they deserved every single second of it.]]

** What Simone, Lena, and Jascque's goals essentially are, ultimately. While it started off as a vengeful assault that was justified against their initial targets who had it coming, it quickly becomes a rejuvenation human trafficking operation where they lure victims into a false sense of security before draining them and adding them to their kills with no higher goal than just living and [[FortheEvulz sadism]]. Being the worst aspect of SerialKiller, natural predators like spiders, and demons- keep their victims in a hellish situation while they enjoy the benefits they steal from others. Far darker than anything the Mystery Inc. has faced before and it wouldn't be until ''WesternAnimation/ScoobyDooMysteryIncorporated'' that something much worse would come along.

** What Simone, Lena, and Jascque's goals essentially are, ultimately. While it started off as a vengeful assault that was justified against their initial targets who had it coming, it quickly becomes a rejuvenation human trafficking operation where they lure victims into a false sense of security before draining them and adding them to their kills with no higher goal than just living and [[FortheEvulz sadism]]. Being the worst aspect of SerialKiller, natural predators like spiders, and demons- keep their victims in a hellish situation while they enjoy the benefits they steal from others. Far darker than anything the Mystery Inc. has faced before and it wouldn't be until ''WesternAnimation/ScoobyDooMysteryIncorporated'' that something much worse who come along.

* [[FamilyUnfriendlyDeath Their deaths too]]. The moment they miss the deadline, their bodies begin sizzling and frying, and we see them howl, snarl, and screech in agony. They look up at the moon and are seemingly able to process that they missed their chance and are now going to pay with their lives before they really begin burning to death. We get to see the flesh vanish from their bodies until they’re left emaciated husks and then watch the fur be fried off of the skeletons, which then crumble to dust. They are completely aware and still alive until the fur begins burning off when their eyes disappear from their skulls as they finally die, where all that’s left is Simone’s necklace and scraps of their clothing. [[AssholeVictim Even so, they deserved every single second of it.]]

** Simone and Lena's midway state, [[CatGirl are from the cuteness normally associated with cat girls]], [[SubvertedTrope being deliberately subverted going conventionally attractive to terrifying]]. Their faces resemble warped, demonic versions of human faces exaggerated to resemble cats with pointed ears, fangs, and yellow cat eyes- looking like something out of a nightmare. Compared to their prior realistic, attractive designs [[UncannyValley the effect is very unnerving]].

** While Simone and Lena being EvilAllAlong is hinted at throughout the film, the sudden revelation of what Mystery Inc. has gotten into is terrifying all on its own. They thought they were investigating more of their usual brand: things like people pretending to be zombies and using special effects... but what they got was a nightmarish human-trafficking scam run by [[SerialKiller demonic feline serial killers that trap countless victims in a hellish limbo over the centuries]], along with said victims being desperate to scare away everyone before they suffer the same fate as them.

** While Simone and Lena being EvilAllAlong is hinted at throughout the film, the sudden revelation that they're humans [[TranshumanTreachery that became demonic feline monsters that both drain their victims and those victims were the aforementioned zombies- trapped in an agonizing fate worse than death- at the hands of their captors for hundreds of years because they want to live forever]]; is terrifying for who out of nowhere it's revealed and the situation becomes even darker than the already morbid scenario the gang just happens to be on an island with real zombies with the residents taking advantage of the zombies, doing some shady schemes- that was the safer and more logical assumption after the revelation that the zombies are real. What Mystery Inc. actually stumbled into is a nightmarish human-trafficking scam run by [[SerialKiller essentially demonic feline serial killers that trap countless victims in a hellish limbo over the centuries]] and they have to stop them to both halt future victims from being added and give salvation to their victims. To say they weren't prepared for this in spite of everything they've done so far, is an understatement

* [[FamilyUnfriendlyDeath Their deaths too]]. The moment they miss the deadline, their bodies begin sizzling and frying, and we see them howl snarl, and screech in agony. They look up at the moon and are seemingly able to process that they missed their chance and are now going to pay with their lives before they really begin burning to death. We get to see the flesh vanish from their bodies until they’re left emaciated husks and then watch the fur be fried off of the skeletons, which then crumble to dust. They are completely aware and still alive until the fur begins burning off when their eyes disappear from their skulls as they finally die. All that’s left is Simone’s necklace and scraps of their clothing. [[AssholeVictim They deserved every single second of it, however.]]

* The scene where Shaggy and Scooby are nearly drained of their life force by the cat-women. As Simone and Lena sadistically grin as they seem to successfully begin their sacrifice, Shaggy and Scooby moan in pain as their faces sink in as the very life drains from their bodies. They slowly become more and more emaciated. And they were alive for every second of it and would’ve been doomed to remain alive if the were cats had succeeded and held them for a little bit longer. For this to happen to the two faces of the franchise, even if it didn’t take, is more than terrifying.

** What Simone, Lena, and Jascque's goals essentially are, ultimately. While it started off as a vengeful assault that was justified against their initial targets who had it coming, it quickly becomes a rejuvenation human trafficking operation where they lure victims into a false sense of security before draining them and adding them to their kills with no higher goal than just living and [[FortheEvulz sadism]]. Being the worst aspect of SerialKiller, natural predators like spiders, and demons- keep their victims in a hellish situation while they enjoy the benefits they steal from others. Far darker than anything the Mystery Inc. has faced before and it wouldn't be until [[WesternAnimation/ScoobyDooMysteryIncorporated Scooby Doo Mystery Incorporated]] that something much worse who come along.

** The kicker: [[TheReveal Terrifying as they are, the zombies were trying to warn everyone away from something WORSE.]]

** Their midway state, [[CuteCatGirl are from the cuteness normally associated with it]], [[SubvertredTrope being deliberately subverted going conventionally attractive to terrifying]]. Their faces resemble warped, demonic versions of human faces exaggerated to resemble cats with pointed ears, fangs, and yellow cat eyes. Compared to their prior realistic designs [[UncannyValley the effect is unnatural]].
*** Their OneWingedAngel into their full forms- they're brown-furred anthropomorphic felines but still have vaguely human faces, [[UncannyValley being an unnatural mix of human and cat]].

** Jacques' transformation is particularly [[JumpScare scary]]. Imagine this [[FauxAffablyEvil seemingly pleasant]] CoolOldGuy suddenly transforming into a [[AxCrazy roaring and vicious]] cat monster, chasing you down with every intention of killing you, either by draining your life force, or to simply eat you alive, as Shaggy and Scooby surely thought while running for their lives. Simone explains that Jacques wanted {{immortality}}, so they gleefully gave it to him in exchange for bringing unsuspecting victims to their island with his ferry. Once he reveals his true colors, Jacques seems much more sadistic and vicious than Simone and Lena. No doubt he was very drunk on power.
* [[FamilyUnfriendlyDeath Their deaths too]]. The moment they miss the deadline, their bodies begin sizzling and frying, and we see them howl, snarl and screech in agony. They look up at the moon and are seemingly able to process that they missed their chance and are now going to pay with their lives, before they really begin burning to death. We get to see the flesh vanish from their bodies until they’re left emaciated husks, and then watch the fur be fried off of the skeletons, which then crumble to dust. They are completely aware and still alive until the fur begins burning off, when their eyes disappear from their skulls as they finally die. All that’s left is Simone’s necklace and scraps of their clothing. [[AssholeVictim They deserved every single second of it, however.]]

** Then there's the subtle MotiveDecay that goes on as Simone continues through her explanation. It starts off somewhat justified as they use their god's powers to avenge their people who died horrible deaths with [[AssholeVictim Moonscar and his crew getting punished for their crimes]], [[TheDogBitesBack with the camera angled downward to show them rising against their enemy like defensive animals rising against a hunter that goes too far]], with Simone suddenly bitter and angry about the whole situation. However, as it continues, they attack an unsuspecting plantation farmer with the camera angle [[IronicEcho with them being the predators on an unsuspecting victim]], [[HeWhoFightsMonsters becoming not only just as bad as Moonscar]], but [[SerialKiller infinitely worse]], considering [[AndIMustScream what they subject their victims to]], with the tone becoming gradually more sinister.

* [[FamilyUnfriendlyDeath Their deaths too]]. The moment they miss the deadline, their bodies begin sizzling and frying, and we see them howl, snarl and screech in agony. They look up at the moon and are seemingly able to process that they missed their chance and are now going to pay with their lives, before they really begin burning to death. We get to see the flesh vanish from their bodies until they’re left emaciated husks, and then watch the fur be fried off of the skeletons, which then crumble to dust. They are completely aware and still alive up until the fur begins burning off, at which time their eyes disappear from their skulls as they finally die. All that’s left is Simone’s necklace and scraps of their clothing. [[AssholeVictim They deserved every single second of it, however.]]

** During this whole scene, the most powerful, nightmarish music you can imagine is playing, appropriate for the breathtaking end of such a powerful nightmare. Seriously, how did the gang ever fall asleep afterwards?

* One of the scariest aspects of the film is how horrifically [[OutsideContextProblem out of their depth]] Mystery Incorporated is. The film is essentially a group of amatuer paranormal investigators in their 20s coming into conflict with a small band of [[NinjaPirateZombieRobot superpowered werecats that drain the life from their victims]], who also use voodoo magic and are backed by some kind of [[EldritchAbomination horrible cat demon or pagan god]]. Can you pull a rubber mask off of a god? No, no you can't. Even the trained police detective is unable to really help in any way. The climax of the film and the defeat of the monsters is ultimately due to the gang getting lucky against insurmountable odds.

** The sheer number of them doesn't help. We never get an exact count nor an idea of how often people "disappeared" on the island, but there's ''at least'' dozens of them from two hundred years of victims. And way too many of them rise up out of the waters and ''quicksand'', implying that much of the surrounding bayou is layered all across with corpses and remains to hide the victims.

''WesternAnimation/ScoobyDooOnZombieIsland'' is widely known for being the first (if not only) installment of the ''Franchise/ScoobyDoo'' franchise to be legitimately scary. While plenty of the later DirectToVideo movies continued the DarkerAndEdgier aesthetic, few can hold a candle to the one that started it all.

** The final deaths of the poor zombies as well, though this is more bittersweet considering their suffering is finally over. They decay, and the flesh is literally torn from their bodies. Morgan Moonscar was approaching the group, but as his body began to rapidly decay, his skull just rattles in place as his spirit leaves his body. Piles of broken bones are left where the zombies once stood, their nightmare finally over.

* Fred's, Daphne's, Velma's, and Beau's faces melting after their wax voodoo dolls get too close to a torch. You can literally see the life leaving them as they melt. Thank goodness Scooby and Shaggy knocked the dolls away in time.

* [[HellIsThatNoise The moans of the zombies sound pretty ethereal and very inhuman]], especially when we first meet the undead Morgan Moonscar. Becomes even more terrifying when later it's revealed that this inhuman moaning and groaning is literally the undead's ''desperate'' attempts to save the gang from suffering their fate.

** The final deaths of the poor zombies as well, though this is more bittersweet considering their suffering is finally over. They literally decay, and the flesh is literally torn from their bodies. Morgan Moonscar was approaching the group, but as his body began to rapidly decay, his skull just rattles in place as his spirit leaves his body. Piles of broken bones are left where the zombies once stood, their nightmare finally over.