When Worlds Collide

I know, there are probably plenty of other crossovers with this title, but I have good reason! there was a Phineas & ferb episode with this title and there was a Pokémon episode called "when Pokémon worlds collide"... you know what, I think I'm over-explaining. this is a Pokémon/Phineas & ferb crossover. it is also my first crossover, so please don't flame.