How do you scare someone safely? How do you build terrifying interactions that are still inviting to try? We've been making novel interactive props using a wide array of technology, uncovering a design language for spooky interaction that has also highlighted how easy it is to make something unintentionally funny, or too difficult to understand, or too frightening to have a go, or too complex to build. It's a complex brief but has yielded a simple set of design questions and approaches that are valuable for any kind of making for audiences, putting the artist's intentionality at the centre of the making process.