Shedinja
This Pokemon is very easy to obtain, but is quite good. It is the only Bug and Ghost type Pokemon. It has 1 HP no matter how high its level, but its special power Wonder Guard makes it almost invincible. Wonder Guard protects against all attacks except for those that are super effective. For example, Bug is weak against Flying types; if someone uses a Flying type move on Shedinja, it is going to get hit. To get Shedinja, you will need a Nincada. You can catch one on Route 116. Make sure you have a free slot for a new Pokemon (Shedinja). That means you can have only five Pokemon, including Nincada. Make sure you have at least one of the type of Pokeball you used to catch Nincada with. For example, if you caught Nincada with a Great Ball, make sure you have at least one Great Ball. Get it to evolve at level 20 into a Ninjask and learns three new moves. Once you are back out to the normal screen, go to your Pokemon. You will see that you just got another Pokemon, Shedinja.