Some could say Eggman, since in Vengeance he is the one that signals the Zombies' initial attack in the the large building, and later on he tries to use one to make Sonic a zombie himself. The experiment malfunctions, instead making Sonic into a "Hornhog" that takes delight in raping his victims to death. And since the Hornhog is not a full Zombie, Eggman cannot control him.
Now taken to the extreme with the clones that appear in Space, where a clone that is activated takes on the personality and memories of their real self's past life. Unfortunately they, minus the first Shadow clone, ally with a Dr. Eggman clone, forcing the heroes to destroy them.
Bad Bad Acting: This series is built off shoddy acting. Here's an example form Vengeance:
Knuckles: Sonic man, I got an idea. We can take up to that.. that crane thing up there that's what it's called I think a crane.
Batman Gambit: Silver's ultimate goal in Vengeance revolves around this. He knew that Sonic and co. would arrive on the island in search of food and shelter, only for zombies to attack, this attack forcing the group to divide up, with Sonic going alone and winding up captured by Eggman, who accidentally makes him into a Hornhog. This transformation eventually triggers Knuckles' appearance on the island (who became a vampire after surviving the nuclear explosion from Origins) leading up to a brawl between Hornhog Sonic and Vampire Knuckles, eventually crossing over into the front grounds where Silver awaits for Sonic to finish off Knuckles, freezes them both at the last second, and snatches both their powers to become the Monster of the Week.
Berserk Button: Don't ever say you used Tails' tacos to summon a giant monster.
Or say you're hungry for one yourself. Amy found this out the hard way.
Camera Abuse: In Gmod, the camera works very much like a tripod. Cue the numerous moments when someone decides to touch it and the camera topples over, sometimes sending it into a spinning frenzy or launching it across the room.
Sonic: Douching through the snow, driving my Hummer, which I don't really need, cause I'm only a single guy!
I'm a Woman, I Can't Help It: During the entire series Amy repeatedly requests to have sex with Sonic, hitting her breaking point in Space, prohibiting her from getting any sleep during the night on Blaze's starship, prompting her to get a clone of Sonic she could have sex with, accidentally releasing a legion of evil clones.
Interspecies Romance: Sonic and Rouge both have sex out in the woods in Diaries, resulting in Rouge getting pregnant.
Tails attempts to get it on with Blaze in Space. It ultimately ends in tradegy following Blaze's discovery of Amy releasing all the clones the main cast had to kill, despite receiving a congratulatory kiss from Blaze after Tails defeats all the clones of himself that also had the hots for Blaze.
Jiggle Physics / Ragdoll Physics: All over the place. Literally every character is dragged around by their head, leaving their other parts to swing around.
Killed Off for Real: Cream is by far the only character that died and doesn't get resurrected in a future episode.
Kill the Cutie: Baby Sonic and Cream are killed off only moments after being introduced.
National Stereotypes: All over the place. The easiest and probably most offensive is Tails' Mexican heritage.
Nice Job Breaking It, Hero: In yet another attempt to "do'' Sonic, Amy instead decides to have sex with one of the many Sonic clones on Blaze's starship, accidentally releasing everyone else's clones, including Dr. Eggman's.
Nice Job Fixing It, Villain: Sort of. If Satan didn't go and announce he used the power of Tails' tacos, he wouldn't be beaten to death by a young mexican fox who suddenly went insane.
Perpetual Poverty: In effect starting from Vengeance; the team repeatedly mentions not eating for days, but no one has shown signs of starving or being physically weaker from the lack of food. For instance, even on an empty stomach, Knuckles is still able to defeat a gang of zombies without receiving any type of body damage or bites.
Power Incontinence: Sort of. Sonic's "Hornhog" form in Vengeance causes him to become hostile and having a thing for raping his victims to death. He can still speak and even questions what happened to him, though the main characters remain scared to approach Sonic in Hornhog form.
Sealed Evil in a Can: Thanks to the logic that any of Blaze's clones that has a living counterpart on Earth that dies in some way inherits the memories of their deceased counterpart, the clone of Dr. Eggman accidentally released by Amy is just as dangerous as the real one Sonic killed an episode prior.
Serial Rapist: Hornhog Sonic. The only one that sees this as a good thing is Amy, since she is constantly trying to get near Sonic.
Spoiler Opening: The preview images for both Origins and Vengeance reveal several key plot elements. Origins' reveals that Knuckles will become zombified and Sonic will have to power up using Rouge's boobs, while Vengeance spoils Sonic becoming a "Hornhog" and the return of both Knuckles and Silver after they were killed off in prior episodes.
Sonic even lampshades the spoiler-tier thumbnails in both Origins and Vengeance.
Swallowed Whole: In Vengeance, Monster Silver kills Shadow this way, however Silver is later impaled on some poles, meaning Shadow could still be alive and escaped from Silver's dead body offscreen.
The next episode Space conforms that Shadow did indeed die inside Silver's body, since according to Blaze, Shadow's life readings have dropped to zero, resulting in the team picking up a clone of Shadow during their visit on Blaze's Starship.
Take That, Audience!: Near the end of Vengeance, Sonic makes a quick stab at viewers who take the series seriously and don't see it as a Stylistic Suck series. Another such stunt would appear in Space.
Too Dumb to Live: Knuckles. While watching over Cream's dead body, he doesn't realize that eventually her corpse would spring back up to bite Knuckles in the arm.
Amy to a certain extent, as revealed by her little "stunt" in Space where she unleashes all the clones while trying to get herself a Sonic clone to have sex with.
Unlikely Hero: In Diaries, it is ultimately Tails that defeats Satan.
Verbal Tic: Sonic's "Whooba Dooba Doo" phrases, especially in Vengeance.
What Happened to the Mouse?: For a series based around zombies, the only scene to contain any form of zombie attack in Space is the opening attack in the deserted city's sewers. The rest of the episode has the team dealing with clones.
Your Soul Is Mine: a "Just The Soul" variety. Silver successfully drains both Sonic's "Hornhog" powers and Knuckles' recently revealed vampirism during their duel. Sonic and Knuckles are Brought Down to Normal as a result.