Tattoos are illegal in Seoul. Rather, a pesky law technically forbids anyone without a medical license from wielding the needles required to craft them. Among polite Korean society, a shock of ink has long been viewed with open disdain, a sign that its bearer was up to no good. Yet the underground body art scene has been quietly gathering steam here, erupting on the Seoul Fashion Week runways this month as the season’s ruling trend—a powerful assertion for individuality that expands the country’s narrow beauty standards.