Unlike traditional rigid-body materials and motor-driving methods in robotics, the emergence of miniature magnetic soft robots (MMSRs) overcomes the limitation of fixed-mechanism structures and allows them to be wirelessly controlled through external fields. At the same time, the presence of new materials and control methods endows MMSRs with potential applications in the clinical field. However, the development of MMSRs is still in its infancy, and needs to be improved in terms of material development, structural design, and sensor modules. This chapter proposes a novel tetherless magnetically actuated miniature soft-body hollow robot design for biological liquid biopsy in the potential clinical field. It achieves the functions of cargo transportation and in vivo sampling by a flexible cavity under a wireless magnetic drive. Moreover, the soft-body structure enables it to accomplish multimodal motions, including tumbling, looper, and oscillation.