Not just for kids!

The 1990s saw the emergence of some of the most popular cartoons to have ever made it to screen, some of which are still extremely popular to this day. There have been some very interesting theories conceptualised by fans of said cartoons. Here are some awesome fan theories about your favourite '90s cartoons.

1. The Powerpuff Girls - The Girls Are All One Person

The main characters were three little girls, who had been created by their "father," Professor Utonium, out of sugar, spice and all things nice. And fans have also theorised that the three little girls in question were actually just the split personalities of one girl with dissociative personality disorder.

2. Doug - Doug Is Racist

Doug was generally fun and light-hearted, but it actually held a very dark secret in that the lead character was nothing more than a delusional racist.

The show featured a titular character who went to school with hundreds of girls of varying skin colours, but who only had eyes for Patti Mayonnaise - literally the only girl of the bunch who is meant to be a white Caucasian.

3. SpongeBob SquarePants - The Characters Are Nuclear Mutants

SpongeBob SquarePants is a hugely popular cartoon and it follows the exploits of a number of colourful characters in their lives under the sea. A theory claims that the show is about nuclear testing - and it's based on some pretty convincing evidence.

Back in 1946, the U.S. government detonated a couple of atomic bombs in Bikini Atoll. The characters in the show were normal sea creatures until this explosion took place and mutated them.

4. Pinky And The Brain - Pinky Is The Genius

"They're Pinky and the Brain, they're Pinky and the Brain. One is a genius, the other's insane!" But which is which?? It might not be as obvious as you think.

But a fan theory advises us to take a closer look at every single episode of the show; Brain comes up with a plan, Brain ignores a very relevant observation Pinky makes, Brain fails and proves Pinky's theory right. It is Pinky who is the genius.

5. Rugrats - Every Baby Is Dead Except Angelica

A creepy fan theory suggests that Rugrats wasn't quite what it seemed, however. Some people believe that Angelica was the only living member of the toddler cast and that the others had died and were figments of her imagination.

It also explains why Angelica is so resentful and it is suggested that in "All Grown Up!" she had become addicted to narcotics, which made her schizophrenia worse.

You may never look at these shows in the same way again.