Giant viruses represent a unique group of viruses that are similar in size to small bacteria. Medusavirus—a special type of giant virus—was first isolated from a hot spring in Japan. Genetic studies showed that medusavirus was more closely related to eukaryotic cells than to other giant viruses, suggesting that it may hold the key to understanding eukaryotic evolution. Although the details of medusavirus morphology and maturation in infected cells have so far remained elusive, the researchers behind its initial discovery now have some answers.