For Pokémon fans, the anime has given enough content for fans to theorize about almost every facet and character. Sometimes, these theories go into a dark place, making a show targeted at children appear as though it's hiding very mature themes. Sometimes, they attempt to resolve differences the anime has with the manga or video games.
Some theories are just hilarious on the face of them. Ash Ketchum's father is missing, so a character seen in the series somewhere else is secretly the missing Ketchum patriarch. It doesn't stop there, though.
10 Mr. Mime Is Ash's Father
The theory that Mr. Mime is actually Ash's dad crosses over into a few other theories. If Ash's real father is a Pokémon, it would explain why Ash has such a strong bond with the Pokémon that he trains. It would also explain why Ash doesn't seem to age, since Pokémon don't age--they evolve.
The anime throws a wrench into this theory since it shows Ash catching Mr. Mime. It can be explained using a common tactic in theorizing, adapting to account for facts that disprove the theory. It doesn't change that weird moment in Alola where Mr. Mime is touching Ash's mother's thigh.
9 Ditto Is A Failed Clone Of Mew
The support for this theory comes primarily from video games. In the anime, a lot of the similarities remain. Ditto and Mew have the same mass. Both of them have similar coloring, although Ditto's more purple hue is closer to another Mew clone, Mewtwo.
In the anime, the theory begins to fall apart since there are multiple Dittos. Of course, the sliding goalposts reason out that the cloning process may have made more than one Ditto. Pokémon reproduction is also something that has always been nebulous, so there's a possibility that Ditto can reproduce asexually, like an amoeba.
8 The Pokémon War Is the Reason There Are So Few Adults
There was a war in the world of Pokémon. One of the Gym Leaders is Lt. Surge, obviously with a military background. He even trains his Pokémon as living weapons and fights brutally, injuring other Pokémon.
In the video games, this theory gets a little dark with Lt. Surge remarked that Electric-type Pokémon saved his life during the war. In the anime, only his military rank alludes to a past conflict within a generation. There is also the rarity of other adults the same age as Lt. Surge, which hints at this theory holding in the anime, although with less nightmare-inducing implications.
7 Everything Is Happening In Ash's Comatose Dream
This is another darker theory that gets more chaotic the longer the anime goes on. The theory starts with Ash getting electrocuted by Pikachu. Ash falls into a coma and everything that happens is part of a comatose dream Ash is having.
It explains all of the different versions of Nurse Joy and Officer Jenny. It makes all of the characters that he encounters different aspects of his personality. Unfortunately, as the anime goes on and new characters and Pokémon get introduced, it becomes less and less plausible.
6 Slowpoke Is Omniscient
Slowpoke is one of those Pokémon that seems incredibly unpowerful and useless. However, there is often a trade-off for a Pokémon being weaker. Magikarp evolves into the incredibly powerful Gyarados. The advantages Slowpoke gains in its evolutions don't quite seem to balance out its weaknesses.
That transitions to the theory that Slowpoke has a very good reason for being so slow. This Pokémon is omniscient, and the constant bombardment of information renders it lackadaisical and unresponsive. This also builds on its eventual evolution into the hyper-intelligent Slowking.
5 Brock Keeps His Eyes Closed Because He's A Gorgon
Around the edges of Pokémon theory is a bizarre idea that Brock's odd "eyes-closed" appearance has a reason. In searching for a reason, the theory came about in Brock's affinity for Rock-type Pokémon. Brock has the gaze of the Gorgon and will transform anyone to stone if he looks in their eyes.
This introduces an ability into Pokémon that has not previously existed. It also makes Brock's motions and ability to function almost contradictory to the theory. It's a theory that makes one do a double-take before eventually discounting it.
4 Legendary Beasts Were Once Eeveelutions
This is a very detailed theory about how the three legendary Pokémon Raikou, Entei, and Suicune were once Eeveelutions. They were created when the Brass Tower burned down a century and a half ago. Ho-Oh, the powerful Pokémon with the power to resurrect the dead and resurrected three Pokémon that died in the destruction, turning them into the legendary beasts.
Given the abilities and types of the legendary beasts, the theory developed that the Pokémon that they came from were Jolteon, Flareon, and Vaporeon. All three are evolutions from an Eevee. The similarities are amazing, albeit ones that make the Pokémon world a lot smaller.
3 Pikachu Is Ash's Father
Traditionally, Pikachu is not a starter Pokémon. Ash got him from Professor Oak because he overslept. However, Professor Oak had one special Pokémon for Ash. Of course, Pikachu tried to electrocute Ash but quickly warmed up to him, becoming Ash's closest companion.
The "proof" behind the theory that Ash's father has his soul trapped in Pikachu, à la Detective Pikachu, is coincidental, but compelling. It relies primarily on events that have not been depicted as happening. However, the idea that Ash is traveling around with his dad on his shoulder is amusing.
2 Ash Ketchum Is A Time Lord
In the bizarre realm of theories around Ash's age, there exists the theory that Ash is a Time Lord from Gallifrey. It ties Pokémon into the world of Doctor Who, where the two have never crossed before. However, if the world of Pokémon is, in fact, a far-future world recovering from near annihilation, time-traveling aliens might not be such a big leap.
Ash's appearance has changed often and he travels with companions, much like the Doctor. The Poké Ball technology involves "bigger on the inside" technology similar to a TARDIS. However, while it explains Ash never aging, occasionally former companions will resurface, also the same age as before. Therefore, as a theory, it has its flaws, other than crossing two different fandoms.
1 Jessie & James Are A Couple
If there's a more popular couple of villains, it has to be James and Jessie from Team Rocket. In the anime, their relationship is close but appears more platonic. The theory of the pair being a romantic couple comes primarily from the Pokémon manga, specifically The Electric Tale of Pikachu.
That manga has an epilogue where James confesses his love for Jessie. It also apparently has a very pregnant Jessie. While the coupling is not considered canon, the anime does have Jessie jealous of James's arranged fiancé. The anime continues to consider the two as platonic and very close friends but canonizing their romance could fully round out their characters firmly as something other than comedic villains.