Well, that's a good question. First, it is not a single saying. You have to take each word individually. "Spooky" is similar to being a little scary. And "Twist" in literature means an unexpected or strange outcome in a story. So a "spooky twist" would mean an unexpected and slightly scary (meant to be fun) ending to a story or plot. I hope this makes sense and helps you.

Hello! In this context: The word "spooky" means sinister or ghostly in a way that makes causes us to be scared or fearful. And the word "twist" is a change in the way in which something happens or when we think something is going to happen in a certain way and it ends up happening in a completely different way. So we can assume that a "spooky twist" means giving information in a way that makes the audience scared and with a surprising end or outcome. I hope that helps!