The visual design of shadows can enhance their menace by playing with contrast, opacity, and sharp angles. Dark, deep shadows with high contrast against the light areas can create a sense of mystery and danger. Similarly, shadows with sharp, jagged edges can give them a threatening and ominous appearance. Additionally, manipulating the opacity of shadows can make them appear more sinister and looming, adding to their menacing quality. Together, these visual elements can create an atmosphere of unease and foreboding in a scene.