In this paper, we developed a universal robot gripper using an electromagnet and a novel reforming magnetorheological (MR) fluid. First, we added nonmagnetic particles to an MR fluid to develop a novel reforming MR fluid called MRα fluid; this fluid resolved several issues faced with MR fluids. The developed fluid's specific gravity is one-half and solidification hardness is two times that of MR fluid. The characteristics of the MRα fluid and an application that can control solidification under a magnetic field are described. Next, the developed gripper, which consists of an electromagnet and an elastic membrane that encloses the MRα fluid, is described. Further, several experimental results of the features and capabilities of the gripper are presented.