I will explain briefly how I made a Creepy Baby Wacky waving inflatable arm flaling tube man. You only need an old hairdryer, an old doll, 2 wires, a soldering iron or some tape, some fabric and some cardboard. Also a switch is useful.
Step 1: Electronics
Using the blower from a hairdryer for this project is reasonably simple. You basically remove the motor and propeller and ditch the heater (we don't need it, it consumes power and might be dangerous for the plastic) en diode bridge (since we will power it with DC).
More details on this step can be found in this nice instructable by another author: https://www.instructables.com/id/Mini-Wacky-Wavin... .
Once you have the motor and propeller, solder some wires to the motor contacts and connect those to a DC adapter plug, including a switch on one of the two wires. What plug? I don't know, just make sure that it fits your 12V adapter... . What switch? Can be any think you want.. I like these flip switches as you can see in the pictures since it fits in the doll's head's mouth =)
Step 2: Mechanics
Buy a doll from a thrift shop and decapitate it. You can use a saw for the hard work. For me also a hot knife to melt the plastic helped. However, be careful for the fumes. Probably highly toxic... .
The doll I bought had some drinking and pissing mechanics so I had to remove all of that stuff. The hot knife came in handy. The hole in the mouth is very useful for my switch.
I also made a hole in the top of the head for the tube.
The tube is made from a light garbage bag. Experiment with different plastics, it has to be light and flexible. A market store bag for example was to stiff I found... . On the plastic tube I fitted two googly eyes to make things more weird.
To hide the hole in the head I took some fabric and made a cap. Saw it inside out to hide the saw marks. I didn't really measure everything, just fit it on the head and cut as you go.
The head's mouth already had a hole that fitted the switch perfectly. If you don't have such a hole, use a drill.
The base, to keep the head up, is just a small cardboard box with some fluo orange tape on it. A little bit crappy but it does the job.