Coral reefs are monsters. Their polyps rise from reefs of their own making—but not just their own. Like the mythical chimeras of ancient Greece, beasts made up of the head of a lion, the body of a goat, and the tail of a snake, coral reefs are made of mismatched parts—animal, plant, and more—that hang together in fragile coordinations. In contrast to jellies, warming waters do not turn corals into bullies; rather, they drive off symbiotic dinoflagellates, weakening the corals. The necessity of working together makes coral life possible; indeed, symbiosis is essential to life on earth. But symbiosis is also vulnerable. Corals, like jellies, are tied to others in rapidly shifting worlds, but for them, disrupted relations lead not to riotous reproduction but to decline and death. In all our vulnerable entanglements with more-than-human life, we humans too are monsters.