Gesugao, a Japanese portmanteau of 'gesu' (scum or vile) and 'kao' (face), refers to a specific trope in anime and manga featuring characters with twisted, wicked, or sadistic facial expressions. Often characterized by shadowed eyes, widened pupils, and a malicious grin, the expression signifies a character revealing their dark nature or relishing in someone else's misfortune. The meme gained massive traction in Western internet culture through image boards like 4chan and art sites like Pixiv, where users began categorizing various characters displaying this 'vile face.' Today, it is widely used in gaming and anime communities to represent a smug sense of victory, a successful prank, or the moment a cunning plan comes together perfectly.