During a spelunking expedition, Palmer and his students, along with his girlfriend, lawyer Jean Loring, find themselves trapped in a cave. In desperation, Palmer secretly uses the lens he has carried with him to shrink himself in order to be able to climb through a small opening in the fallen rocks sealing the cave, knowing he will likely explode. Using a diamond engagement ring, Palmer enlarges the hole sufficiently and descends to the floor to try to alert the others of the escape route before dying. However, upon entering the lens' beam, he finds himself returned to normal size and without danger of exploding. As the lens is covered with cave moisture, Palmer believes this has altered the beam to allow this strange effect. When subsequent experiments still result in objects exploding, Palmer concludes some unknown force in his own body allows him to safely size-shift. He decides to use this effect to become a superhero. A retcon in "Brightest Day: The Atom Special" (July 2010) removes the influence of his exotic physical makeup, tying his survival instead to the discovery of a "compression matrix," a fabric able to spread the effects of the ray on the entire body, stabilizing it. The prototype matrix later became his costume.