In S2 E17, the non-anthropomorphic dog Nova falls from a helicopter and sent to the hospital. She remains in a coma until flatlining, only to be possessed by an interdimensional alien, rendering her actual status somewhat unclear.
In the Season 1 finale, Shaggy is sent to military school and Scooby is sent to an abusive farm instead of kept by Shaggy's parents. The farm is briefly seen in the following episode.
Somewhat bittersweet ending. All of reality is destroyed and every side character the audience has come to know is killed. When reality resets, history has changed and none of the side characters retain their memories from throughout the show. The gang are shown to be a little sad at having less mysteries to solve in this new reality.
Fred is often neglected by his father in Season 1. To a lesser extent, the other gang members minus Velma all have neglectful parents. Furthermore, Fred's real parents in Season 2 attempt to kill him at least once and are major antagonists.
As mentioned under other entries, Nova the dog and Pericles the parrot both die. The series' finale antagonist, a demonic interdimensional alien, also dies.
Fred is neglected and kind of emotionally abused by his adoptive father in Season 1. Late in Season 2, when encountering the good part of his father in the sitting room, Fred forgives him, but added context is necessary in that at this point, Fred's real parents have been shown to be *much* worse than Fred's adoptive father ever was.
All side characters die in the series finale. Fred's angered reaction to his adoptive father's death is shown, and he is seemingly indifferent to his evil biological parents's deaths. If one looks closely, the shot before Daphne cries shows her mother being picked up by the Evil Entity, to be eaten.
In the series finale, the Evil Entity "bathes" the world in fire, making it apocalyptic and fiery, bringing Hell to mind. Although not referred to specifically as a demon, one can argue that he / his Anunnaki minions kind of are demons.
Fred departs Crystal Cove in the Season 1 finale to find his real parents after his adoptive father is arrested. After an unspecified amount of time passes, Fred is disheveled and has a stereotypical homeless look at the beginning of Season 2 (played for laughs). After his real parents betray him, Fred starts living in the Mystery Machine by the river until Daphne invites him to stay in one of her mansion's spare rooms.
In thie episode, the main monster is tons of cicadas making up a giant cicada form. They often are shown up close and can be seen "attacking" victims in genuinely disturbing ways (eg. While driving, while in the shower).
None of the five Mystery Inc members die. Other major characters are not so lucky. The series finale does however reset reality, and any deaths are undone, but they are sort of depicted as different version of the previously deceased characters, who do not return with their memories.
S1 E17: the implied offscreen death of Danny Darrow. S1 S26: the explicit offscreen murder of Ed Machine. S2 E11: the offscreen death of Cassidy. The last two episodes of Season 2 also contain lots of deaths.
All side characters die in the series finale. Fred's angered reaction to his adoptive father's death is shown, and he is seemingly indifferent to his evil biological parents's deaths. If one looks closely, the shot before Daphne cries shows her mother being picked up by the Evil Entity, to be eaten.
The series contains stronger horror tropes and homages than other Scooby-Doo media. So basically, jumpscares? Yes. Although mild enough to only be effective to very young children.
Closest to this is the parrot antagonist Professor Pericles getting knocked unconscious by Mayor Jones, who places something like chloroform over his face. Pericles' eye is permanently scarred and presumably blinded.
Sort of… a location in the fright hound episode is an asylum for criminally insane animals, and animals in this universe are very capable of being sapient.
No, and autism is not referenced in any way in-series, but showrunner / producer Mitch Watson confirmed that this incarnation of Fred is canonically autistic. With that in mind, Fred is portrayed with special interests and limited social skills, but he is still a 3-dimensional character who is very capable of handling himself.
Not in a transphobic way, but at least once or twice a character refers to Velma as a boy, much to her annoyance. One example of this is in Season 2 Episode 18.
Marcie is confirmed by showrunners to be romantically involved with Velma. This is implied but not confirmed directly in-show. She is violently killed offscreen, but not because of her sexuality. When reality resets in the following episode, she is still alive.
A black woman is one of the few deaths in the series. I can't recall if she was first, but considering there's about 5 total character deaths, it can still leave a sting in someone's mouth.
The Kriegstaffebots, recurring antagonists in Season 2, very frequently use their gatling guns. Nobody is shot, until S2 E25, when recurring character Marcie is very clearly shot to death, but this is not shown onscreen.
Danny Darrow stays in his underground house when it collapses in on itself, but what actually happened to him is not shown. Whether or not he survives is not stated, but the implication is there that he died.