These cartoons of your past have some bizarre fan theories involving death, racism, nuclear radiation, and some other totally messed up stuff.
Hey Arnold: The truth about Arnold's parents and his disease
via creepypasta:
In the show, Arnold is presented as an orphan who lives in his grandparents' boarding house. Some think that his grandparents are actually his real parents and because of a pregnancy so late in life, there were serious complications with Arnold's birth. He was born with hydrocephalus, a condition which causes a buildup of water in the brain, augmenting the size of the head—this accounts for Arnold's football-shaped head. Beyond that, conspiracy theorists also think that Arnold's friends are imaginary: he uses them to escape reality.
Source: fanpop.com
Rugrats: All the babies are dead and/or imaginary figures
via nerdacities:
All of the Rugrats are dead and figments of Angelica's imagination. Chuckie (the anxious redhead) died with his mother, which explains why his father, Chaz, is such a mess. The main character, Tommy, was a stillborn and his death had a lasting effect on his father: Stu's obsession with making toys stems from the trauma of losing his son. As for Phil and Lil, the twins with slightly ambiguous genders—their mother, Betty, had an abortion. Knowing that Betty was pregnant and then not, Angelica didn't know the sex of the baby and thus created twins to include both sexes.
Source: showbizgeek.com
SpongeBob SquarePants: Victims of nuclear radiation
Source: wegotthiscovered.com
According to one redditor:
The existence of Spongebob and his strange friends is the result of radiation from nuclear arms testing that was performed on the Bikini Atoll in the late 40's and early 50's. Since they live under the atoll, the town is known as 'Bikini Bottom'.
