Flow

A fleeting but intriguing presence in the DC Universe, Flow made their debut in Grant Morrison and Howard Porter's landmark JLA run in 1998 — one of the most celebrated and ambitious periods in Justice League history. With only a handful of appearances, Flow is a rare, blink-and-you'll-miss-it figure from that electric late-'90s era, sharing pages with heavy hitters like Wonder Woman, Green Lantern, The Flash, and Plastic Man. For devoted Morrison completists and JLA scholars, tracking down this elusive character is exactly the kind of deep-dive treasure hunt that makes comic collecting so rewarding.