In Spine, while there isn't a direct equivalent to the Path Deformation feature from Inochi2d, you can achieve similar effects using Mesh Deformation and Path Constraints. Mesh Deformation allows you to manipulate the vertices of a mesh directly, providing a high level of control over the shape of your attachments. You can read more about it in the Meshes - Spine User Guide. Path Constraints can be used to control the movement and rotation of bones along a path, which can indirectly affect the mesh if the bones are influencing it. However, Spine does not currently support animating individual bones along a path directly, which might be what you're looking for. You can explore creative solutions by combining these features, or consider runtime solutions for more complex deformations.

bapho In Spine, only bones can be directly bound to meshes. Bones can be constrained using paths. Additionally, paths can be bound to bones, allowing you to constrain bones bound to meshes using paths and further control those paths with other bones. By applying physics constraints to these control bones, you can achieve the same setup.
However, if there is no specific reason to use paths, the combination of meshes, bones, and physics constraints alone is sufficient to achieve the effects demonstrated in the video.

In any case, if you want to learn more about setting up the use of paths, I recommend reading the documentation for Stretchyman, one of the example skeletons:
https://esotericsoftware.com/spine-examples-stretchyman