Ok, I sort of left out some key parts in my first photo. Before I build up any unjustified anticipation, I'll show you what I've done. Nothing too special, just slapping together some parts I had. Well, I had to buy the PVC pipe and related accessories.
If you said scarecrow... ding, ding, ding! You're correct.
I have a couple of these plastic mannequin torsos. I bought them a few years ago to take product shots of shirts. Haven't done much with them since, so why not run some pipes through them and make a scarecrow? First I used this hole cutter to make 2" holes in the shoulders. It's made of thin plastic.
There, now we have ports for his pipe arms. This mannequin torso is modeled after my body, by the way.
I cut hole in the center of the back, so I can see the meeting point of the pipes, and attach to them to this cross fitting. I bought some PVC cement but I don't think I'll use it. It's pretty secure as is, just dry fit. So by not cementing the pipes together, I'll be able to disassemble him for storage. While on display, he'll have arms spread over 5 feet, and will be around 7 feet tall.
I'll be using this pumpkin mask on top. I cut a piece of PVC pipe to come out of the neck, which is the height of the interior of the mask. So his head will stay nicely propped up.
This is just a quick test, but if gives you an idea. Some spooky shredded fabric added, which I may cut into some shape. I bolted eye-hooks onto the ends of the pipes, so I can hang a lantern, and possibly something else on the other side. I will be painting the PVC black to blend into the night, and will maybe add some sticks (with black plastic cable ties). Might also put flickering LEDs in his eye sockets. He'll be standing in the front yard (held up by a heavy umbrella stand), ready to greet trick-or-treaters. I'll post final pics after Halloween.