my life has only known joy since i learned of elysia chlorotica
E X Q U I S I T E
Eastern Emerald Elysia (Elysia chlorotica), family Plakobranchidae, found along the East Coast of the United States
This creature engages in kleptoplasty, taking the chloroplasts from the algae that it eats, and using the chloroplasts for the waste products they create though photosynthesis. Its kind of a... solar powered sea slug!
These sea slugs are not nudibranch, but are in a different order of gastropods.
image via: Views of Elysia chlorotica from Martha’s Vineyard. Figure 15 of Krug et al., 2016, Zootaxa 4148:1
image via: Karen N. Pelletreau et al. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0097477