This material sounds pretty incredible, it's a metal alloy of some sort embedded in a flexible mold that can switch reversibly between solid and liquid shapes by controlling the temperature or by reversing the polarity of a surrounding magnetic field. Currently it can be used to solder electronic components and assemble parts in hard-to-reach spaces, remove foreign objects or deliver drugs in a model stomach. >they uniquely combine high mechanical strength (strength, 21.2 MPa; stiffness, 1.98 GPa), high load capacity (able to bear 30 kg), and fast locomotion speed (>1.5 m/s) in the solid phase with excellent morphological adaptability (elongation, splitting, and merging) in the liquid phase. *** >As shown in Figure 1E, a MPTM figurine molded in the shape of a Lego minifigure escapes from a cage by transitioning to a liquid phase and being pulled through the cage bars by an external magnetic field. After escaping, the liquid MPTM restores its original shape by flowing into a mold. *** >MPTMs exhibit an enabling combination of fluidity in the liquid phase and rigidity in the solid state, which correspond to a modulus change of nearly four orders of magnitude *** This is a long, in depth research paper. It also describes some of the current limitations of the material as well as mention that it can be induced to split or merge back together. I'm putting this in Science rather than Tech because it seems to still be in the early stages of development.