California blackworms constitute a recently identified animal system exhibiting unusual collective behaviors, in which dozens to thousands of worms entangle to form a “blob” capable of actions like locomotion as an aggregate. In this paper we describe a system of pneumatic soft robots inspired by the blackworms, intended for the study of collective behaviors enabled and mediated by such physical entanglement. Both the robots and worms have high aspect ratio ($\gtrsim 1: 50$), intertwine in complex 3D configurations, operate both in air and underwater, and can locomote both individually and as a collective. We demonstrate and characterize locomotion for both individual robots and entangled blobs, explore the tunability of entanglement strength, and compare these to the analogous versions in living worms. The robots provide a testbed for studying mechanisms underlying behaviors observed in worm blobs, as well as serving as a platform for studies of novel collective behaviors based on physical entanglement.

Osmosis-driven actuation offers a promising strategy for developing untethered, environmentally responsive soft and shape shifting mechanisms and robots. In this work, we explore the use of superabsorbent polymer (SAP) pellets as large-scale, shape-morphing actuators. Upon exposure to water, these approximately 2mm diameter spherical pellets undergo a dramatic volumetric expansion, up to 300 times their initial volume, generating actuation forces of approximately 10 N under constrained conditions. We further demonstrate reversible cyclic actuation via controlled swelling-deswelling using ethanol-water solutions. Finally, we integrate these systems into a shape-morphing wheel design to enable adaptive locomotion that passively transitions between terrestrial and aquatic environments. Our findings demonstrate SAP-based osmotic actuators as an environmentally-driven solution for soft robotics, and shape-shifting soft hybrid mechanisms.