You could buy a HalloWing from Adafruit and build something around it: https://www.adafruit.com/product/3900

Many Halloween effects can be done with a simple wiper motor: https://www.youtube.com/channel/UCeBxc0fj-UUayo01ei0B7wQ

Also very popular for instructions: https://www.youtube.com/channel/UCKKBTwYyVYxkpa0_9pqQ13A Steve Koci, the creator, has sadly passed away, but his book "The Ultimate Guide To Do It Yourself Animatronics" might be worth a look.

Adafruit + SparkFun: Great for beginner-friendly electronics (servos, sensors, microcontrollers).

Arduino-based Halloween projects on GitHub – lots of open-source code for motion + sound effects.

YouTube channels like Make:, Animatronics How-To, and DIY Creature Workshop often show step-by-step builds.

If you want to go deeper, look into Raspberry Pi-controlled props for more complex movement + audio sync.

For something quick and spooky, even a simple PIR motion sensor + servo motor setup can create a fun jump-scare effect.

The current issue doesn't seem that Halloweeny, but if you can get the back issues they are fun to have for decor, too.

Toby Horrorboy is great:

https://youtube.com/@tobyhorrorboy

Search YouTube for “Furby Hacking”.

Buy some used Fur Real animatronic toys for a few bucks from Facebook marketplace and hack on them with your kids.

Make a spooky UFO scavenger hunt in the park with electronic gadgets.