What you need to do this project is:
-Wood- You need to build the animatronic's armature out of something. Wood seems to work just fine. I used scrap wood that I had around the house.
-Small Oscillating Fan- This is what I used to animate the prop. The Grim Reaper would turn his head from side to side.
-Skeleton Mask- I found one at Party City on clearance for $2.99. It worked...
-Black Sheet- Dress up your Grim Reaper. I actually used a black tablecloth.
-Sickle- The Grim Reaper carries around his sickle. I made one out of a palm tree branch. Get creative.
Step 1: Build the armature
How exactly you build it doesn't make all that much of a difference either. All of this will be covered up, so as long as the frame holds up, it will work. An important feature of my design is to put a flat piece of wood at the top of the frame, where the neck would appear to be. This is where the fan will go, so it should have a stable place to sit. Build your armature accordingly based on how your fan will fit into the frame.