When You See It (often abbreviated as WYSI) is a classic internet phenomenon involving images that appear normal at first glance but contain a shocking, scary, or humorous detail hidden in the background. Popularized on early image boards like 4chan and Reddit, the format relies on the viewer's 'aha!' moment when the brain finally processes the anomaly—often a face in a window or a misplaced object. It pioneered the 'mindfuck' genre of internet media, evolving from simple scary pranks to complex optical illusions and humorous social commentary, remaining a staple for engagement-driven content across social media platforms.