Soft robotics provides a promising framework for achieving compliant and adaptive manipulation in unstructured environments. Among biological models, the octopus represents one of the most compelling inspirations for both biologists and roboticists. The octopus arm is a canonical example of a muscular hydrostat, a fully soft and skeletal-free structure capable of sophisticated manipulation through continuous bending, axial elongation and shortening, and localized stiffness modulation. Its ability to generate complex movements without rigid elements makes it an ideal blueprint for next-generation soft robotic manipulators. This thesis investigates the intrinsic passivity of the distal tip, whose mechanical contribution to overall arm behaviour remains insufficiently understood.