How to creat those round edges? I found this "Ghost" image online, and I tried recreating it in Blender.



I started with a Cube then applied a Subdivision to get the head, but my problem was creating the tail.



How to get that perfect rounded tail? 

I even tried it with Cylinder instead of Cube, still failed. :(
In my opinion, you should sculpt it, but if you want to model it here is an example: