The Sewer Horse, also known as the Basement Horse, is a quintessential example of a 'cursed image' that gained internet notoriety for its surreal and slightly menacing aesthetic. The image features a horse’s head emerging from a small, dark opening in a concrete floor, which is often interpreted by viewers as a basement drain or a sewer entrance. While its exact origins are unclear, the image began circulating widely on platforms like Tumblr and Reddit around 2015, quickly becoming a staple of weird internet culture. It is typically used to represent something lurking, unexpected, or absurdly out of place. The meme often leans into the 'boss fight' trope or serves as a reaction image for moments of inexplicable dread or bizarre encounters.