Somebody once told me that if...

a. you have a nincada (bug Pokemon)

b. have one extra spot in your Pokemon party with no Pokemon in it

c. Have an extra poke-ball

then you can get two Pokemon by evolving nincada. You get Ninjask, the bug, and shedninja, the shell. Shedninja has the wonder guard ability. Though it only has 1 HP. Good Luck!