If you have can successfully make a tiny bat from polymer clay, the bat's body and wings make good candidates for simple molds made from two part silicone mold putty. Very small amounts of two part silicone mold putty are required and the resulting molds will easily make extra bats for your scene. Mix small amounts of both of your two part mold putties, then gently place a baked bat body and baked wings face down into the mold. Run a flat knife across the top of the mold to make sure it is as flat as possible. This will make it easier to use after it has set. Once the mold putty has set, the molds can be filled with polymer clay and baked in the oven to the temperature required by the clay, or they can be filled with epoxy putty, which is left to harden. Some polymer clays will harden stiff enough in the molds that a pin can be used to remove the bat's body and wings for baking separately from the mold. You will have to experiment with your particular clay.
The molds work well for these little miniatures as the backs of the bat's are fairly flat. If you have made roosting bats (bats with their wings wrapped around their bodies) you can also make molds from these, but you may need to gently shape the back of the bat, and you will have to color the wings with paint as molds this small are hard to use with multiple colors of clay.
