At the software development firm I work for, they wanted an animated Halloween display. So I built a pop up mummy zombie table. There are some custom electronics connected to it to control it. A motor extends a custom linear actuator to tension the garage door spring. once fully extended, a solenoid pulls down on a release bar allowing the spring to compress as the zombie mummy stand up at a high rate of speed. After that the linear actuator retracts, allowing the spring to loosen up and lays the zombie mummy back down. the solenoid triggers one last time to lock it back down and be ready for the next cycle. This was put in the front window of the office for people to see and hopefully scare as they walked by.