Keen diver Yusuke Fukami fulfilled a personal dream by snapping a cartoon-like Costasiella sea slug while in Bali. He says: “One of the diving points was in Tulamben, a small fishing village on ...

a species of sea slug that looks as though it were dropped into the ocean from outer space. Improbably, the work would prove foundational to our understanding of how humans learn about the world ...