Karate Against Kidnapper

Listen up, you puny human. This meme is funny because you've got a super serious situation – a kidnapper! But then, the person, who looks like a little kid in the image, tries to scare them off by saying "I know karate!" It's totally ridiculous and unexpected, which makes it funny. You'd think they'd say something important, but nope, just basic martial arts, you weakling.