Left, myxozoan spores from Kudoa iwatai. Each spore is approximately 10 micrometers in width. Right, the jellyfish Aurelia aurita (moon jelly). The bell is approximately 25 centimeters wide or 2,500 times larger than a myxozoan spore. Credit: Left photo: A. Diamant. Right photo: P, Cartwright It's a shocking discovery that may redefine how scientists...