Alakazam's brain continually grows, infinitely multiplying brain cells. This amazing brain gives this Pokémon an astoundingly high IQ of 5,000. It has a thorough memory of everything that has occurred in the world. (Sapphire)
Let's break this one down a little:
Brain continually grows: Okay, no big deal - literally everyone's brain is constantly growing and adding new brain cells. Nothing big here.
"Infinitely multiplaying brain cells": Uh. Okay. 'Infinitely' is a strong word. 'Infinitely multiplying' is a really strong phrase, indicating that the brain cells are damn near infinite after a cycle or two. An infinite number of brain cells woud be, well, infinite. They would take up all known space, and then some. So let's just assume this means "a whole bunch" and someone got carried away.
"IQ of 5,000": The highest recorded IQ ever is 228. This knocks that out of the park by around 4,800 (which is a whole bunch). And given Pokemon probably shouldn't be able to do well on a test designed by and for humans (you may remember that Pokemon have limited speech capabilities, essentially animal-slave versions of Hodor), it's pretty crazy to imagine he has a higher IQ than the number of years Great Britain has existed.
Gardevoir has the psychokinetic power to distort the dimensions and create a small black hole. This Pokémon will try to protect its Trainer even at the risk of its own life. (Sapphire)
Listen, Gardevoir - we all know you mean well, that you try to protect your trainer at all costs - but creating a black hole (even a small one) is a bad move. Ya see, black holes have a near infinite density, with gravity so powerful that not even light can escape its surface. They devour matter like its nothing. Maybe you shouldn't just be creating them two feet above the ground. Just a suggestion before you end all life on Earth.
Volcanoes erupt when it barks. Unable to restrain its extreme power, it races headlong around the land. (Gold)
Entei cannot speak any language other than Pokemon-ese (which, sadly, probably isn't even understandable to fellow Pokemon, since each Pokemon can only say their respective name) - so let's just assume any time it wants to vocalize anything, its a bark. That's a lot of volcanoes erupting all the time - especially since its description isn't limited to 1 volcano eruption per bark. If Entei ever hears a thunderstorm, it would probably drown the entire planet in lava. Well, at least exploding magma isn't as hot as Macargoes.