My PacMan frog isn't moving. What is it doing?

Live Pac-Man frogs are sometimes mistaken for dead Pac-Man frogs. When their substrate dries out and/or food is scarce, the Pac-Man will encase itself in a tough outer skin to protect it from drying out. They won’t move and they look like they are dead. Once rehydrated, however, they will shed this outer skin (and eat it!).