The last half of season two involves a curse where it's said that the dog will die. S2E14: A dog getting electrocuted (no visible injury) and is seen lying still on the ground. He is transformed into a cyborg and lives. S2E17: A dog falls from a height (no visible injury) and is alive but unconscious. S2E18: A dog is seen lying in the hospital.
A main character ends up living in the mystery van after running away from home. Same character is also shown travelling across the country with stereotypical ‘hobo’ outfits and is implied to be homeless for several months.
S2E1: Scooby is briefly shown locked in a room alone, boredly bouncing a ball against the wall. When trying to escape, he gets shocked by an electric fence, as well as chased by a man with a gun. However, Scooby escapes unharmed.
No but Scooby is put in peril several times. If you want to stretch a bit, he fights a robot dog in one episode but in unrealistic ways such as operating machinery
Not particularly gory, but one character has a scar across one eyelid that partially blinded him. It is revealed that he got this injury when another character threw him to the ground.
[MAJOR SPOILERS] It’s revealed that Fred Jones Sr is not Fred’s real father but actually kidnapped him from his birth parents in a hostage situation and raised him as his own
The town Sheriff is horribly incompetent and has made countless false arrests, all of his incompetency and abuse of power is played for laughs + he is overall a sympathetic character
A couple scenes in the Animal Asylum for the Criminally Insane. Several comments made throughout the series that strongly imply Daphne's mom has been institutionalized/hospitalized on a few occasions, and unfortunately these tend to be played off as humorous rather than serious.
There are several episodes with racial charactures. Some episodes have villains based around misrepresented cultures. Some episodes have side characters (like Marmalade and Chachinga) who are either stereotypes or some sort of stereotype related joke.
All the apocalyptic destruction and character deaths are undone via resetting the timeline, Fred and Daphne get engaged, and the gang goes on more cross country mystery solving adventures after graduation