cast mod

Cast Modifier

This modifier shifts the shape of a mesh, curve, surface or lattice to any of a few pre-defined shapes (sphere, cylinder, cuboid).

videos

Notes:

https://docs.blender.org/manual/en/dev/modeling/modifiers/deform/cast.html?highlight=modifiers

It is equivalent to the To Sphere tool in Edit Mode Mesh ‣ Transform ‣ To Sphere, Alt-Shift-S and what other programs call “Spherify” or “Spherize”, but, as written above, it is not limited to casting to a sphere.