Geuseundae appears as darkness itself and is told as a lethal cousin of the Eoduksini, the dark that swells the longer you stare up at it. Where the Eoduksini is a crushing weight that grows under your gaze, the Geuseundae is the version where that mass finally becomes a hand that kills.
What makes it unsettling is that the line between harmless dark and lethal malice never resolves. Whether it always meant to harm, or whether the watcher’s own gaze called the shape into being, is left sealed.