First I sculpted the bat out of sculpey. For reference, I took my video camera with Night vision into the Haunted Mansion at Disneyland and took video capturing the details in close-up-so scaled 1-to-1/actual size and it's pretty close to being "on-model" as they say in my biz.)
Then I took it to a friend who helped me make a mold out of silicon (which captures every single detail-even fingerprints! That's how accurate it is!)
When they came out, they turned out great! They were made to fit onto a standard size PVC pipe. The Halloween that I made these, I was in a hurry. They were finished literally the night before Halloween. My friend showed up with them and I thought they were going to be cast in a hard resin but because of time (again) he only had time to have them cast in self-skinning foam (like a NERF footbal, etc.) I tried mounting them onto the PVC but as soon as I connected a chain between them, they slumped over because they didn't have enough strength. So I had to stick a metal pole inside of them to give them a frame/structure (the wings still sag, though).
I also faux-finished them to look like brass by first painting them with a base coat of black paint then dabbing a gold color over the black. (people think they are for real until they touch them.)
Here's the finished product.