How do I defeat a Shedninja (Lv100)?

You need to hit Shedinija with an attack that is super effective on it. Shedinja's Ability(Wonder Guard) negates all damage unless it's a Super-Effective hit, OR a Weather Condition

Shedinja is Bug/Ghost. Let's look at his weaknesses:

Bug loses to: Fire, Flying.
Ghost loses to: Ghost, Dark.

Hit 'em with one of those type of attacks, OR just get an attack like Hail, Sandstorm, or get a Tyranitar because his ability is Sand Stream, which causes a Sandstorm.

Also, Shedinja only has 1 HP, so it automaticlly faints if it gets hit.

One Word: Flamethrower!!!!

Use a flying move or something that is super effective because he has only 1 hp and his ability is to block all attacks except super effective ones so use a flying-type move.

Use a Rock, Fire, Flying, Ghost, or Dark type attack. You can also use Sandstorm or Hail, or poison, burn, or confuse it. Shedinja is incredibly easy to defeat, as long as you know at least one of these moves.

Shedninjas can only be killed using supereffective move.. Like fire n pyhic

Well, it probably has Wonder Guard huh? You need to either give him a status effect that hurts him (poison, burn, or have a sandstorm going), or hit him with an attack that would be considered super effective and that also matches one of the types of your attacker.

~SGX

To defeat a lv100 Shedninja you need is a lv70 or higher psychic Pokemon because shedninja is a bug/ghost and psychic attacks are really powerful against him so next send out a psychic pokemon.

I hope I helped.

~skyline_2fast_luffy~

The Shedinja's level is not important. Because of his 1 HP, he is dead in no time. The ability Wonder Guard makes it a tricky opponent.

Just use a move that is a weakness of a bug or a weakness of a ghost. There is no need to use a flamethrower when even ember can make him faint.