Originally, the universe had been a "Cosmic Egg" — a primal sphere of disorganized, dense, compact primordial matter. The sphere underwent a "Big Bang," an explosion that hurled the matter outwards, where much of it eventually condensed into stars and planets. This universe expanded in size for billions of years, and then contracted, undergoing a "crunch" over the following billions of years. All of the matter of that universe was plunging towards a central point, where it was collapsing into a new "Cosmic Egg."

When the universe was in its final stages of collapse, Taa's civilization was one of the last still in existence. Lethal radiation caused by the "Big Crunch" this universe was experiencing was wiping out all life across the universe. Galan, a space explorer, was dispatched to travel through the cosmos to find a means of saving Taa, but he found none. The radiation eventually killed off all but a tiny fraction of the population of Taa. Knowing their deaths were inevitable, Galan proposed to the remaining survivors that they die gloriously by piloting one of their starships directly into the heart of the "Cosmic Egg." As the starship containing Galan and his fellow survivors approached the focal point of the Big Crunch, the heat and radiation killed all the passengers except Galan, who was transformed by the sentience of that universe into the World-Devourer Galactus.^[1]

• Taa being from the Sixth Cosmos is a retcon. In the original telling of Galactus' origin story from Thor #169 (1969), there was no mention of previous universes and the Taa-ans were wiped out by a plague; Galan got his powers from a star. When the origin story was retold in Super-Villain Classics #1 (1983), the dialogue was modified (all mentions of the plague got reworked into radiation poisoning from universal decay), the sun got changed into the terminal point of the universe, and the Sentience of the Universe was added.

• Earthquakes on Taa were called Taa-quakes.^[2]