This octopus-inspired smart skin can change shape and reveal hidden secrets on command.

Q: Tonca, an American alligator snapping turtle, was the unofficial mascot of the Museum of Science & History in Jacksonville. He made a memorable impression on many who saw him through the years.

The researchers turned to hydrogels, which are water-rich, jelly-like polymers that respond to temperature and chemicals. But instead of layering different materials or embedding electronics, they ...