The grey stripe on the side of the scorpion is soft. It is the "skin", also refered to as the pleural membrane and if it sustains damage, the scorpion, in a nutshell, can "bleed" to death. When the scorpion molts, the exoskeleton is shed, revealing the complete membrane which keeps the scorp's body withheld. They are very fragile and it is never recommended that a scorpion be handled or fed during molt. Molts are one of the main purposes of specific humidity levels with certain scorpions, as with their overall basic adaptations.