[[caption-width-right:273: Sonic ? Is that... you ?]]

* ''Sonic's Scream Test''. Eyes aren't supposed to look like that...The ghosts from that episode definitely wouldn't be out of place in a horror film.
** [[https://youtube.com/watch?v=xVYqGtsbPcQ Don't forget about that moment where]] [[DemonicPossession Amy gets possessed!]] [[NotHerself Sweet]] [[NightmareFace dreams]]...
* Episode 27 showing Eggman's iconic method of placing animals into his badniks ''while they are still conscious, [[AndIMustScream frantically screaming and trying to get out]]''. Granted the blow is lessened when you realize the badnik is [[MinionWithAnFInEvil E-102]] [[IronWoobie Gamma]], but it's still rather horrifying...
* For some people, Dark Super Sonic. OH YEAH, [[PunctuatedForEmphasis ''The. Dark. Super-Sonic.'']] Even Eggman was worried and unsettled about it, to the point of convincing Sonic to [[GetAHoldOfYourSelfMan calm down.]] For all he knew, Dark Super Sonic might've gone on to kill the rest of them.
** It's especially scary because Sonic is normally a pretty laid-back guy; seeing him get [[RageBreakingPoint so angry]] [[SanitySlippage to the point]] where he transform into ''[[SuperPoweredEvilSide some monstrous kind of supreme being]]'' who's dark, [[SuperStrength super-powerful]], and also eventually AxCrazy, that's [[BewareTheNiceOnes utterly frightening]].
** In the English Dub, Sonic's voice doesn't change too much aside from sounding very pissed about what happened to Chris and Cosmo. In the Japanese Dub, however, Sonic's voice turns dark very quick. After seeing a terrified Cosmo and unconscious Chris, his voice trembles with shock at first, but it soon becomes [[TranquilFury silently indignant]]. And when the carnage begins, he [[ScreamingWarrior screams bloody murder]] as he [[UnstoppableRage rips the robots apart.]]
* [[spoiler: The Final Mova, in all of it's forms, really. Not helped by the fact that, [[HeroicSacrifice had Cosmo not intervened at the last moment]], [[ApocalypseHow the whole galaxy could have pretty much gotten destroyed.]] ]]
** [[spoiler: Special mention still goes out to the very first form - a three-headed dragon that is basically a fusion of the three surviving Metarex generals that, near the end of episode 75, practically ate Sonic alive. He does escape, but still...]]
* Episode 60 had an eerie tone to it, even going so far as to have one [[UncannyValley giant creepy eyeball watching over Sonic, Knuckles, and Amy through most of the episode,]] and the disembodied ScaryTeeth floating in the air near the end. What's even creepier was that the "scary" castle they were in for the whole episode was [[GeniusLoci indeed self-sentient.]] Granted, it WAS just a Metarex, but still...
* The Metarex in general are pretty messed up. They [[ApocalypseHow destroy their own planet, and then attempt to wipe out any life that isn't plant life]]. They even kill their own members if it helps them, and Dark Oak [[AdultFear really has no concern for his (implied) daughter, Cosmo]].
* Episode 73. [[spoiler:It's basically Shadow hunting down Cosmo for the most part and if you're familiar with his strength, speed, and capabilities, then you know for sure you can't stop him from causing harm even if you tried. In fact, this is exactly what the Sonic cast was doing only to get pushed aside so easily. Of course, at the end of the episode, the crew was able to stop Shadow from running off away with Cosmo... but still the thought of [[BloodKnight the ultimate life form trespassing in your headquarters with the intent of ''harming you or a best friend'']] is [[ParanoiaFuel fear-incarnated.]] ]]
** The worst part? [[spoiler: They finally get Shadow off the vessel, via using the Sonic Driver cannon. They think they're safe... and then [[ImplacableMan Shadow]] arrives again. It's just due to coincidence that he didn't murder the entire crew.]]
* And in the very next episode after that, we have some seriously [[FridgeHorror horrifying implications]]. [[spoiler: Long story short, the tracking device in Cosmo's brain can be removed...But at the cost of leaving Cosmo [[AndIMustScream deaf and blind for the rest of her life]]. And it's very likely that the Metarex intended on that.]]
** [[spoiler: Even not taking Cosmo's possible fate into account, just imagine how horrifying it must be - to know that you basically betrayed the people that you considered friends, all because of your own cowardice. To say that Cosmo [[BreakTheCutie didn't take it very well is an understatement.]] - at one point, she even contemplates escaping the Blue Typhoon and going on what is basically a suicide mission. Sure, everyone does convince her to stay, but once again - Cosmo's part of the episode just runs entirely on FridgeHorror.]]
** The episode also has some incredibly unsettling reveals - At first we have minor things, like [[spoiler: Cosmo turning out to belong to the same species as the Metarex]], but then things go downhill really fast - namely, the backstory of Dark Oak/[[spoiler:Lucas]] - [[spoiler:his home planet was basically stuck in a never-ending war against an unknown threat, with many of his fellow seedrians either getting killed off en masse, or dying from overexertion after entering their [[DangerousForbiddenTechnique Final]] [[OneWingedAngel Form]] - the latter seemingly being even more threatening, because even '''children''' were entering their Final Forms despite knowing what consequences it will bring. As a result, the leader of the seedrians, Earthia (Who was also Lucas' wife and the mother of Cosmo and Galaxina) decides that the seedrians must abandon their home planet, while Lucas insisted that the seedrians stay behind and fight, and as a result, the seedrians split into two factions - Earthia's followers (Seemingly all female), who decided to abandon the doomed planet, and Lucas' followers(Likely all male), who decided to fight no matter what. Eventually, all of the vegetation on the planet begins to quickly die out - a result of Lucas [[PoweredByAForsakenChild harvesting the planet's life energy]], all for the purpose of using it to stabilize the seedrians' Final Forms. Needless to say, Earthia wasn't very pleased with this, which results in the conflict between the two factions escalating even further, to the point where, even after the war was over, Earthia ordered to ''[[NukeEm nuke the planet]]'' before she and her followers left the planet, so that no survivors whatsoever will be left. Unfortunately for her, Lucas' followers and Lucas himself had survived, and later became the Metarex.]]
** So, in short, in that episode alone, we have [[spoiler: a both [[UnwittingPawn unwilling]] ''[[UnwittingPawn and]]'' [[UnwittingPawn unwitting betrayal]], a chilling possibility of an innocent eight-year old ending up in an AndIMustScream scenario, and a villain backstory that involves both interplanetary and civil war, planetary-scale environmental abuse, child soldiers sacrificing their own lives, and an '''attempted genocide''' by usage of '''[[NukeEm nuclear weapons]]'''.]] You know...[[WhatDoYouMeanItsForKids For kids!]]
* Knuckles punching Yellow Zelkova so hard that ''the spikes on his hands break off'', followed by both combatants screaming in pain.