The Spherify modifier distorts an object into a spherical shape. This modifier has only one parameter: a Percent spinner that deforms the object, as much as possible, into a spherical shape.
Spherify shapes the dog inside the snake.
The success of the operation depends on the topology of the geometry to which it's applied. For example, a cylinder with no height segments will result in little change. Adding height segments will result in a barrel at 100 percent. Adding cap segments will produce a sphere.
Try this on a teapot.
Example: To use the spherify modifier to distort a teapot:
Example: To animate spherifying a teapot: