Tinshel

It forages timidly for seeds and insects, never straying far from cover, and at any alarm it withdraws entirely into its metal shell and clamps shut, a hard little box that most predators eventually abandon. As it grows it must find and move into a larger shell, and this exchange is the most dangerous moment of its life, a brief scramble of soft vulnerability between one armor and the next. Tinshel gather where old shells are plentiful, and a good supply of vacant casings will draw a whole shy, clattering community of them to the same stretch of rock.