Christopher Chance and Cosmo shared a few things in common. Each man used strategy and cunning as vigilantes, while adopting the modus operandi of international playboys. Also, they were supreme masters of disguise. Additionally, each were featured in the same comic book, with Chance's Human Target appearing in Detective Comics #483-484, 486, 493, 500, 515 and 518 and Cosmo's Phantom of Disguise appearing in Detective Comics #1-37.
While Chance had the professional name as the Human Target on his native Earth-One, on Earth-Two it was Cosmo, the so-called Phantom of Disguise who filled the same type of niche. And what was this occupation, you may ask.
Well, turns out both heroes likes to draw out the criminal element while protecting innocents by by impersonating the criminal's attempted victims. As such, both men built reputations in this field, causing their legends to grow over time.
Although Chance would on occasion team up with fellow heroes such as his world's Batman, Cosmo operated before the original Batman debuted and seemingly retired shortly after his first appearance. More is the pity, considering the tales that could have been told!