Comic Title: World's Finest Comics #173
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: February 1968
On Sale Date: December 12, 1967 Newsstand Date December 12, 1967
Source: Direct Currents, Atom #35, Page 31

Copyright Date December 12, 1967
Source: Library of Congress, Periodicals 1967

Frequency: Monthly, with the exception of Jan., April and July
Cover Price: $0.12
Page Count: 32
Editor: Mort Weisinger

Title: "The Jekyll-Hyde Heroes"
Pages: 18

Feature(s):
Superman (of Earth-1)
Batman (of Earth-1)

Writer: James Shooter
Penciller: Curt Swan
Inker: George Klein

Reprinted In:
Showcase Presents:World's Finest Vol. 3 TPB (2010)
Batman Arkham:Two-Face TPB (2016)

Feature Character(s)

• Superman (last appearance in Justice League of America #60; next appearance in Superman #204)
• Batman (last appearance in Justice League of America #60; next appearance in Brave and the Bold #76)

Supporting Character(s)

• Robin (last appearance in Batman #199; next appearance in Detective Comics #372)
• Lois Lane (last appearance in Action Comics #359; next appearance in Superman #204)
• Jimmy Olsen (last appearance in Action Comics #359; next appearance in Action Comics #361)

Villain(s)

• Dr. Aaron (a criminal scientist; no further appearances)
• Kralik (a space villain; in flashback; no further appearances)
• Members of Intercrime (no further appearances)

Other Character(s)

• An unnamed test subject (no further appearances)

Cameo Appearance(s)

• Two-Face (a statue)
• Joker (a statue)
• Catwoman (a statue)
• Lex Luthor (a statue)
• Brainiac (a statue)
• Parasite (a statue)
• Prankster (a statue)
• Toyman (a statue)
• Puzzler (of Earth-1; a statue)

Synopsis:
Dr. Aaron is apprehended by the World's Finest Team for illegal human science experiments. When he gets out of jail, Dr. Aaron decides to take his revenge on Superman and Batman. First he learns which of their villains that they fear the most, then he uses psyche-distorter chemicals on them. The chemicals cause physical and psychological transformations which turn Batman and Superman into Two-Face and the space villain Kralik.

As Two-Face and Kralik, the former heroes begin attacking Metropolis and each other. Robin deduces that the heroes have been turned into villains, but he is captured by Dr. Aaron before he can summon help. However, when Batman in his Two-Face guise decides to kidnap Dr. Aaron himself, the scientist is forced to drink his own chemicals. He becomes the Composite Superman and defeats the villains. Superman and Batman then return to normal, but Dr. Aaron reveals that the chemcials will have an after-effect on him, leaving him a hopeless lunatic.