Creating Blob Shape

Hi,

I'm relatively new to Rhino. I'm trying to create a 'blob' shape in grasshopper, it can be a mesh or surface.  I've viewed this post: http://www.grasshopper3d.com/forum/topics/making-curve-blob but it hasn't helped.

Essentially what I'm trying to do is merge a number of spheres (see the image attached) into a continuous blob shape. I've experimented with trying merge spheres in grasshopper, but nothing has worked. I don't mind if the solution is to merge the spheres or create a blob shape completely from scratch.  

I've also attached the grasshopper definition I'm working on. Creating the blob form is just a part of the large definition. I want to create the blob form to subtract from a larger solid.

Any help is greatly appreciated!