Up and Out

In this novella, first published in 1957, a young couple, Gor Goginog and Rhitha, experience the great dual atomic explosion which ends the world, and smashes the planet to smithereens.
Cast into space on the last tiny green scrap of the Earth's surface, they encounter the only other remaining beings from the dead planet, a couple blown up to their scrap by the force of the blast. Org is a composite creature, created by vivisectionists - part walrus, part fish, part bird - in fact made of a huge number of different animals' body parts. With him is his partner, Asm, who is human like Gor and Rhitha.
As Gor, Rhitha, Org and Asm spin on through space, they philosophize about the catastrophe which has taken place, deal with stars who want to commit suicide, and encounter a Time-monster in the shape of a huge forked-tongued slug, through whose body they are pulled to the ultimate Void beyond. There they discover the utter abjectness of Eternity, and watch it swallow itself.
In the empty grey space beyond Time, they are visited by Mathonwy, the star Aldebaran, Kwangtse, Buddha, and some Greek gods arguing in a cloud, everyone discussing all the while, building revelation upon revelation, as the realisation dawns that the whole universe wants to kill itself! Finally, in a tumultuous capstone section, God and the Devil are their culminating visitors, in a conversation with the four which sometimes seems augustly impressive, sometimes a delightfully funny and petty argumentative chat. They all six come to a momentous decision together, which will change everything.
By the 1950s, John Cowper Powys had lived a very long life packed full of philosophical speculation. His thoughts had ranged far and wide, examining many of the world's systems of thought and religious understandings. His extraordinary primary powers had engendered a way of marshalling them all, in profound relation to each other, and in relation to himself. Now, in his old age, he was inspired to begin on a short fantastical eschatological work which encompassed these ideas. The result, Up and Out, is one of the most eccentrically original pieces of fiction ever written.