To get shedinja, you must first catch a nincada, and have an empty space in your party. people say you need a pokeball for it, but you do not. shedinja copies the ball the nincada was caught in. Shedinja appears when you evolve nincada into ninjask, providing that there is a pokeball of some sort in your backpack and a space in your party, you will get shedinja. the way the pokedex explains this is that when nincada evolves into ninjask, it leaves it's original shell behind.. To get the other form of nincada (which is shedinja) you need 5 spaces in your party including nincada and at least one pokeball. then you need to get nincada to level 20. it will then evolve into a shedinja. in the space that was empty, you also get a ninjask. first you must catch a nincada at any level under 20..
