This was one of our first attempts at making an animated prop, and also using Monster Mud. We're pretty happy with the result. The dragon's mouth opens and closed, with fake flames in the mouth. Its wings also flap. We decided to just do the upper torso of the dragon. So it has arms and wings, but we skipped the lower half. It stands at about 6 feet tall. Here is a basic "How-to" on the dragon.
Biglots had a bunch of animated yard decorations. Including a frog, whose mouth opens and closes. We figured this would be the simplest way to get the mouth to move on the dragon. So we took the head off the frog, and used some wire to get a basic shape for the dragon head.

 

We then used Monster Mud over the frame to build the head. Here's some different angles for the head. We also used strips of flame colored plastics attached in the mouth. We later used orange and yellow lights, along with a fan to blow these strips, to make it look like flames were coming out of his mouth.

 
For the body, we opted to use PVC. I found a picture of a dragon whose pose I liked, and used "Paint" on my computer to get a general idea where the PVC would go. Then had to just piece it together. Later on we added a PVC stand to the bottom of this design, to make it more sturdy.

 
Next we used some styrofoam and pool noodles to give the arms some girth. For the wings, we took an animated butterfly (from Biglots) whose wings flap, and attached it to the PVC frame. We then used some thin metal rods, wire and pool noodles to create the shape of the wings. We also started wrapping the PVC frame in chicken wire. Zip Ties were our best friend for a lot of this process! Got packages of 100 for $1 from American Surplus.

 

Here's a couple of close ups of how we attached the butterfly to the PVC Frame. You can also see the motor mechanism. It's kind of hard to see from the pictures. We mainly used zip ties to attach it. They work really well for cinching things down very tightly.


The next step was to monster mud the body, and attach the head (again with zip ties). We positioned a fan directly behind the head to blow the plastic strips. For the eyes, we cut holes in the monster mud, and used a hot glue gun to place a clear, round piece of glass to the inside. We then added LED's behind the glass.


The hands were made from pool noodle foam, wire and monster mud.


Then we added some final touches. A bit more monster mud where needed, wings, teeth and spikes on his spine. The motor for the wings wouldn't handle much weight, so we had to keep things as light as possible. So we used very light cloth attached to our wings frame. Since trick or treaters view it from the front, it didn't matter that the butterfly wings and the fan show from the back.


And the final product!


A picture of the dragon in our 2004 haunt. We had dragon roars and growls synched with his mouth movements. And we had a fogger blowing around him. Occasionally the fan in the back of his head would suck in some fog, and spew it out his mouth. It looked awesome in the dark!