That Pokemon you are referring to is called missngno. It, so far cannot be destroyed.Even if you were to try to release it,it will come back. the best advice for now is LEAVE IT IN THE PC FOREVERRRRR! those are the so called consequences for messing with the game. It is extremely cool to show to your friends but do not,and i repeat do not open its stats, as it will freeze instantly.
you cant
All you have to do is fill the Pokedex completeley. There are some pokemon which you will have to trade from white but you can do it.
If you are talking about the question marks in the pokedex, then you have to catch them, trade them, or find an action replay code. If you need more help on where to find them, go to www.serebii.net.
teach a flying Pokemon defog and use it
you can't!
You can go to the Move Deleter in Canalave City.
There is no "Foggy city" in Pokemon Pearl it is a route celestic town you can use defog ( a hm when you beat the 4th ) to get rid of the fog.
If you hacked a Pokémon or even received a hacked one then you need to release them and get an action replay to get new Pokémon or just start over on your host Diamond/Pearl/Platinum and/or delete your file on Pokémon Battle Revolution.
You cant until you reach the Pokemon league
Use repel. You can buy one at the Pokemart (blue roof).
u cant if u want to get rid of a Pokemon just put it in a PC then click it if it says release press it and it will be gone if ur not getting rid of a Pokemon then u cant
The solution depends on what version you're playing. Usually, depositing you Pokemon into a box will fix this glitch. Alternativly, try taking your Pokemon to the Name Rater's house to change the nicknames.