Kind of. He fell into a huge container that contained molten steel.
He was taken to the hospital. The doctors were able to save his life, but they couldn't get the steel out of his belly.
"That's okay," Nautilus said. "Now I can take a good punch to the gut. You wouldn't believe how many people want to beat me up."
With that the doctor punched him in the gut. While the doctor was shaking his fist in pain, Nautilus went on, not having felt a thing, "See what I'm talking about!"