The last stage of an Ocampa's roughly nine-year life, marked by rapid physical and mental decline, which an aged Kes had reached in the alternative future of Before and After.
The morilogium is the name the Ocampa give to the closing phase of life. Because the species lives only about nine years, old age arrives abruptly: memory fails, the body weakens and death follows within a short time.
It is depicted in the Voyager episode Before and After. The story opens with Kes as an old woman in sickbay, surrounded by a daughter and grandson she does not recognise. The Doctor is about to place her in a bio-temporal chamber, a device he has built in the hope of extending her life by pushing her cells back to an earlier state.
The treatment interacts with chroniton particles lodged in her body since a Krenim attack years earlier, and Kes begins to slip backwards through her own life in jumps. Each leap takes her to a younger age, until the crew of an earlier time manage to purge the chronitons and restore her to the present.