Researchers identified jorumycidine, a new hexacyclic marine alkaloid from the nudibranch Jorunna funebris and its dietary sponge, Haliclona sp., and demonstrated that it exhibits potent nanomolar cytotoxicity against multiple myeloma cells. They also proposed a new biosynthetic route involving cross-species metabolic interplay and an unusual oxazolidine ring that may help stabilize a pharmacologically important scaffold.