The slug eats plants and the algae chriomosomes in the slug make food for it up to nine months:-http://www.sciencedaily.com/releases/2015/02/150203155925.htm-"The authors present the first direct evidence that the emerald green sea slug's chromosomes have some genes that come from the algae it eats.-"These genes help sustain photosynthetic processes inside the slug that provide it with all the food it needs.-"Importantly, this is one of the only known examples of functional gene transfer from one multicellular species to another."