Shedinja's moveset is pretty written in stone...
Shedinja- [atk + / def -] @ lum berry/choice band
EV: atk and speed
-protect
-3 highly offensive attack
Shedinja can be killed by...
-super effective attacks (such as ghost, flying, fire, etc)
-burnt status damage
-hitting-oneself confusion damage
-leech seed
-toxic/poison status damage
-spike
-weather damage (hail and sandstorm)
-Tyranitar's appearance (auto OHKO with sandstream)
-destiny bond
-struggle (either side)
-curse from a ghost