Add a warp shader under the simple shape, add a vector displacement shader as function input of that warp shader and use a PF as input for the vector displacement shader, which combination will push and pull the edges of the circle about. Then play with values, and see what happens. Too much and the circle will 'desintegrate', so it takes some experimentation. Or a simple fractal warp can do a lot to that simple shape shader (SSS), but is less controlable.
