The phrase most likely refers to the 5th Wave book series by Rick Yancey or its 2016 film adaptation , which holds a 5.2/10 rating on IMDb . The series is a prominent sci-fi thriller ("Sci-FiThri") often categorized in "Top 10" lists. Guide to The 5th Wave Series
: Available at Amazon , this collection includes mid-range rated cult films like The Monolith Monsters and The Mole People . Recommended "10/10" Sci-Fi Thrillers 5.5 / 10 Sci-FiThri...
If your search for "5.5 / 10" was a typo and you actually want top-tier "10/10" recommendations, experts and readers on Reddit and Goodreads suggest: The phrase most likely refers to the 5th