Kleptoplast

KLEP-toh-plahst n.

STOLEN GREENS  Sea slugs can steal light-harvesting chloroplasts and keep the cellular bits for months, but not all thieves use the material.

Sven Gould and Jan De Vries/Hhu Düsseldorf, Center for Advanced Imaging 

A cellular part such as a light-harvesting chloroplast that an organism takes from algae it has eaten. Some sea slugs hold on to these stolen chloroplasts for months.