Because it's only a matter of time now until one of those things absorbs a human brain, and launches it's chlorophyll fueled plot of world domination.
Sea slug sustains self with photosynthesis - Winnipeg Free Press
Research led by University of Florida biologist Sidney Pierce shows the emerald marine creature Elysia chlorotica -- which shares North Atlantic coastal habitats with a species of algae called Vaucheria litorea -- has evolved, over countless millennia, to absorb some of the plant's photosynthesis-enabling genes into its own DNA.
Sea slug sustains self with photosynthesis - Winnipeg Free Press