Figure 1. Leech-inspired liquid metal robots for reconfigurable circuit welding and transient electronics. (a) Schematic illustration and photographs showing the reversible shape transformation of a leech (Movie S1). (b) Schematic illustration showing the elongation, deformation, splitting, and coalescence of a liquid metal droplet robot. (c) Schematic illustration of an electronic circuit. In this circuit magnetic liquid metal is used as a reconfigurable conductor for the on-demand circuit welding. (d) Optical photograph a carbonyl iron:Galinstan composite (1:9 mass ratio) in a mortar after mixing. (e) Photographs of carbonyl iron:Galinstan composites at different mass ratios. In (d) and (e) the liquid metal was in contact with air. (f-j) SEM images showing the surface morphologies of the magnetic composites with different mass ratios. (k,l) EDS maps showing the uniformity of the distribution of carbonyl iron powder in the gallium indium tin alloy matrix at low (k) and high (l) mass ratios.