A green sea slug appears to be part animal, part plant. It's the first critter discovered to produce the plant pigment chlorophyll.
The sneaky slugs seem to have stolen the genes that enable this skill from algae that they've eaten. With their contraband genes, the slugs can carry out photosynthesis — the process plants use to convert sunlight into energy.
"They can make their energy-containing molecules without having to eat anything," said Sidney Pierce, a biologist at the University of South Florida in Tampa.