When you use a totally bullshit argument that has absolutley nothing to do with the case. This term comes from the popular TV show South Park
I hope Johnny Cochdoesn't use his famous Chewbacca Defense.... This is Chewbacca, Chewbacca is a Wookiee from the planet Kashyyyk, but Chewbacca lives on the planet Endor. Now, think about that. That does not make sense! Why would a Wookiee - an eight foot tall Wookiee - want to live on Endor with a bunch of two foot tall Ewoks? That does not make sense! What does that have to do with this case? Nothing. Ladies and gentlemen, it has nothing to do with this case! It does not make sense! None of this makes sense. If Chewbacca lives on Endor, you must acquit! The defense rests. DAMNIT!