In the past few years, we have covered plenty of cool bio-inspired robots here. This soft swimmer is inspired by the manta ray. This is an energy-efficient soft robot that can achieve a swimming speed of 3.74 body length per second. This is lightweight design weighs 2.8 grams.
This robot has a soft body and a pair of flapping wings. Its body bends up and down with pressurized pneumatic air. More information is available here.