It began in Milan in 1981 with the Memphis Group, led by Ettore Sottsass — reportedly named at a party where Bob Dylan's "Stuck Inside of Mobile with the Memphis Blues Again" kept playing on repeat. It was a deliberate revolt against Bauhaus and Swiss style's restrained "form follows function," closer to "form follows fun."
Visually it means free-floating zigzags, squiggles and confetti shapes, saturated primaries clashing against pastels, and black-and-white grid patterns (one of its signatures). The point isn't harmony but deliberate mismatch.
Dismissed as dated for a while, it resurfaced from the late 2010s in Gen-Z-facing branding and app illustration. Today it mostly appears scoped down — a background pattern, a decorative illustration element — rather than covering a whole layout.