Oh, to Be a Blobel!
"Oh, to be a Blobel!" is a science fiction short story by Philip K. Dick. It was first published in Galaxy magazine, February 1964. The plot centers on the post-traumatic psychological state of former espionage agents on both sides of the Human-Blobel war. Blobels are presented as a single-cell, protoplasmic species prevalent in the outer solar system. Espionage agents on both sides of the conflict underwent irreversible physical modifications, enabling them to assume the form of the opposing species for a defined time period each day. The story deals with the ramifications for agents' personal and social identity from this alteration.
George Munster is a veteran of the war with the Blobels, in which he was decorated for bravery. He was selected for a special assignment as a spy and altered to be able to appear in Blobel form. After the war he has a small pension but for half of each day he faces an involuntary reversion into Blobel form and so cannot marry or keep a job. Eleven years after the war he seeks help from a homeostatic (robotic) psychoanalyst that introduces him to Miss Vivian Arrasmith who was his opposite, a Blobel spy on earth. When released she was unwilling to return to Titan due to the shame of being in human form for almost three quarters of each day. They overlap in human form for about seven hours each day. They get married and have three children, one Blobel and two hybrids, Vivian is pregnant with their fourth child, which they assume will be “a full-blooded Terran” because of the Mendel’s Law. They are not welcome in Terran society, especially their hybrid children and George becomes suicidal. Eventually, George finds a money-making scheme at which he can be successful, an electromagnetic reducing belt that Vivian helped design. He is in the process of trying to get a factory started on Io, when Vivian finds out that he is having an affair. She takes the children and goes to Titan, where she is able to get the latest medical treatment and in order to save her marriage, she chooses to be stabilized in human form. She then returns to Earth but George has accepted the terms of the Blobels to build a factory on Io. He has become a citizen of Titan and taken on Blobel form permanently. George finally feels successful.
"Here I nailed down the ultimate meaningless irony of war; the human turns into a Blobel and the Blobel, his enemy, turns into a human, and there it all is, the futility, the black humor, the stupidity. And in the story they all wind up happy”. (1976) 
- Philip K. Dick, “The Minority Report and Other Classic Stories” New York: Citadel Press (ISBN 0-8065-2379-4, $14.95, 380pp) page 380.