Giallo is a kind of movie or book, usually one with a lot of suspense and mystery. The word "giallo" comes from the Italian word for "yellow," which was the color of the covers of many mystery novels in Italy. Giallo stories usually feature detectives, horrific violence, traumatized victims, and many twists and turns. They often contain elements of horror, science fiction, and psychological thrillers. They can be scary and thrilling, but they also usually suspenseful, so they're usually exciting to watch or read.