A reader from South Africa (Durban, South Africa, more precisely) wrote to us about two hammerhead worms that he found in his home. He was wondering if hammerhead worms are harmful or dangerous to animals or babies, and he was also keen to discover what is causing them to enter his home. So, the question before us is this: are hammerhead worms harmful to humans or animals (like pets), and how do you get rid of hammerhead worms? (Technically, the reader didn’t ask how to get rid of hammerhead worms, but he was wondering how they got into his house, and in answering the latter we also answer the former.)