Two ‘Thecacera sesama’ feeding on a bryozoan. Ho-Yeung Chan et al., 2026. Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. By signing up, you confirm you are 16+, will receive newsletters and promotional content and agree to our Terms of Use and acknowledge the data practices in our Privacy Policy . You may unsubscribe at any time. Small as a grain of rice, polka-dotted, and everything nice. These are some of the ingredients that come together to make Thecacera sesama , a newly identified species of sea slug , or nudibranch , found swimming in Taiwan. “Taiwanese divers call it ‘sesame’ in Chinese and it is also small like a sesame seed, hence the name,” researchers explain in a statement . Indeed, T. sesama is less than 0.12 inches long.…