A portrait of the Echo-Answering Worm from Edo-period essays and tales. Marked by high fever and a sore like a mouth on the abdomen, its voice echoes the host’s words and at times spews curses. It craves food and drink, and refusal is said to raise the fever. Cures attempted include prayers and decoctions, especially a method of selecting and combining drugs it dislikes, then administering them so the creature weakens and later exits the body. Some accounts describe a lizard-like form with horns, though appearances vary widely. Chinese lore of the echoing parasite merged with Japan’s notion of the human-faced sore, emphasizing a mouth opening in the belly. Attempts to exhibit the illness for profit were recorded, though families often refused for shame. Its origins span materia medica and storytelling, long understood as a disorder set at the boundary of medicine and the uncanny.