Question

Do the games or anime ever describe what is it like inside a Pokeball?

Comments

Interesting question... I don't think the games ever said so but someone else might know about the anime.

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If I remember correctly, the inside of a PokeBall is an artificial, virtual world, with an enviroment that conforms to the needs of the Pokemon residing in it.

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Right!

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Pikachu dosnt like it....

Answer 1

To put it in a few simple words, not necessarily.

In some episodes, they have an open Pokéball
![][1]

[1]: http://farm6.static.flickr.com/5243/5337247602_1efda169d9.jpg

So the inside of a pokeball is only what you believe it to be (Or whatever they decide to show you)
However, you did go inside the pokeball in Destiny Deoxys when the movie started.
But no, they never described specifically what was inside the pokéball

Answer 2

The anime once showed Iris's Dragonite inside it's pokeball, but it could also be seen as just a humorous scene.