I've added an "arm tool" to the editor. This allows you to define arms on both the non-Squishy Squishies and to an actual Squishy instance, meaning that when the game starts Squishy can already be attached to objects. Can't really explain this properly but never mind.
One upshot is that you can now send signals to the non-Squishy Squishies to make them release their arms.
I've also finally got around to improving the fire system when objects are on fire. This was basically based upon implementing a RandomPointOnBody() method that takes a b2Body (Box2D's body type).
The method then selects a shape at random. If the selected shape is a circle, it picks a point by choosing a random normal vector and scaling it by a random value between 0 and the circle's radius.
If the selected shape is a polygon, it decomposes it into triangles then selects one at random. It then picks a random point on the triangle using this method.
Now a body composed of any number of shapes has the fire spread across it in a nice even and random manner.