Yoshii's Moment Of Realization

"Iron."

"Understanding blasted him. 'Douse your flash!' he yelled. 'Get back inside!'" (15, p. 110)

"'Douse your flash, I said. Can't you see, bright light is what causes the trouble?'" (ibid.)

Yoshii and Carita have landed on a planet where a single super-molecule, naturally selected to assimilate new material and now covering the entire surface, has begun to eat their spaceship, a greater threat than the kzinti who meanwhile are searching the system for them, in fact yet another instance of the outer enemy.