The defossilization process isn't perfect, and everal pokemon would have different types if it was.
Kabutops: Bug/Water
Omastar: Steel?/Water
Aerodactyl: Dragon/Flying
Armaldo: Bug/Water
Rampardos: Dragon
Archeops: Fighting?/Flying
Carracosta: Fighting/Water
Tyrantrum: Fighting/Dragon
Aurorus: Normal/Ice

>>24771991
While a lot of these typings are retarded, I don't think the part about them not being rock type is even headcanon. Fossil pokemon are all rock type because they came from fossils.

Here's getting the way too common ones out of the way:
>The legendary hamsters used to be Eeveelutions before they died in the Brass Tower
>Giovanni is Ash's father
>Ash Ketchum is immortal

And a personal headcanon of my own:
>In the Pokemon world, the "chicken or egg" question is called the "Arceus or Mew" question, and the "choke a smurf" question is about Colbalion instead of smurfs.

Ash Ketchum is aro-ace.

no wait that's canon

Fuck you OP, best headcanon is Mew/Arceus discussion

>>24772012
It's too late anyway, I already mentioned the Arceus or Mew question.

Ash is in a coma and has been since season 1

Ash never ages because at the end of the first episode he sees Ho-Oh, seeing Ho-Oh is apparently a way to obtain eternal happiness, for Ash, eternal happiness is staying a child trainer forever

The series goes through a time loop each Season, hence why Ash never ages and why Pikachu always reverts back to level 5

>>24771991
>>24771997
Mega Aerodactyl is implied to be the original form of Aerodactyl prior to extinction, and it's rocky as fuck. The headcanon that only Rock types were preserved honestly makes more sense than the headcanon that they had different typing before.

DexNav Pokemon, which comes with HA and Egg Moves, are Pokemon that were released by trainers and the DexNav allows you to "recover" them.

Any Pokemon can be a Starter Pokemon. The ones known as Starters are given to you because you were at the correct place and moment.

Gift Pokemon are always 87.5 (M) because they are endangered Pokemon. Lapras, which the Pokedex says that is almost extinct, is 87.5 (M)

Despite unnecessarily dark headcanons insisting that Pokemon battles should end in death, it's actually illegal as fuck to kill Pokemon unless it's in self defense or for food these days. Official battles end in fainting because everyone knows to restrain themselves. Trainers don't kill wild Pokemon because they aren't trying to get fined.

>>24774350
>>24774442
These