How does Pikachu have a Colosseum Pokedex entry, but no one else does?

[anhJer]

Hello, I was looking through Pokedex entries, and noticed that Pikachu has a Pokedex entry, but no other Pokemon in Pokemon Colosseum does.

Does Bulbapedia just not have them, or do they not exist? Whats even more confusing is Pikachu isnt even in Colosseum.
anyone know whats up? thanks

Sources:
Pikachu: Pikachu (Pokémon) - Bulbapedia, the community-driven Pokémon encyclopedia
List of pokemon in Colosseum: Pokémon Colosseum - Bulbapedia, the community-driven Pokémon encyclopedia

 

[Gengarzilla]

If Pikachu really is the only Pokémon with a Colosseum entry, I'd... actually not be surprised. It's the freaking mascot of this franchise.