Comic Title: Adventure Comics #500
Publisher: DC (DC Comics Inc.)
Address: 666 Fifth Avenue, New York, NY
Cover Date: June 1983
On Sale Date: March 3, 1983 Newsstand Date March 3, 1983
Source: House Ad, Amazing Heroes #19, Page 17

Newsstand Date March 3, 1983
Source: Amazing Heroes, #20

Newsstand Date March 3, 1983
Source: Comic Reader, #209

Shipping Date February 8, 1983
Source: Comic Reader, #209

Copyright Date February 15, 1983
Source: Library of Congress, Copyright Office 1983
DC publication dates beyond April 1981 listed by the LoC
represent shipping dates NOT newsstand sale dates

Frequency: Monthly
Cover Price: $1.75
Page Count: 144
Editor: Nicola Cuti

See Also: The Guide to DC Giants

Title: "The Secret of the Mystery Legionnaire"
Pages: 12

Feature(s):
Legion of Super-Heroes (of Earth-1)

Writer: Jerry Siegel
Artist: John Forte

Reprinted From:
Adventure Comics #305 (1963)

Feature Character(s)

• Legion of Super-Heroes (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Cosmic Boy (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Saturn Girl (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Colossal Boy (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Brainiac 5 (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Sun Boy (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Shrinking Violet (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Bouncing Boy (last appearance in Adventure Comics #304; next appearance in Adventure Comics #306)
• Invisible Kid (last appearance in Adventure Comics #304; next appearance in Adventure Comics #307)
• Mon-El (temporarily uses the aliases "Marvel Lad" and "Legionnaire Lemon" (Lemon is an anagram of Mon-El) in this story; last appearance in Adventure Comics #304; next appearance in Adventure Comics #308)

Villain(s)

• Jax-Ur (last appearance in DC Comics Presents #97; no further appearances)
• Unnamed Phantom Zone criminals (no further appearances)

Other Character(s)

• A Sun-Eater (not to be confused with the Sun-Eater in Adventure Comics #352; no further appearances)
• Antennae Boy (a rejected Legion applicant; next appearance in DC Comics Presents #59)
• Dynamo Boy (a rejected Legion applicant; no further appearances)
• Monsters of the planet Brogg (no further appearances)

Cameo Appearance(s)

• Superboy (in flashback)
• Lightning Lad (as a corpse and as a statue)

Synopsis:
After rejecting two candidates for membership, the Legionnaires meet a worthwhile hero, Marvel Lad, or "Legionnaire Lemon," who demonstrates all the powers of Superboy and Mon-El, but not their weaknesses to Kryptonite and lead. By the end of the day, he passes their initiation by retrieving the rare mineral fluvium, defeating a Sun-Eater, vaniquishing the monsters of the planet Brogg, and creating an anti-gravity metal. After being told that they will induct him the next day, he vanishes.

The following day, he appears – and reveals himself as Mon-El. He explains that Brainiac 5 had secretly developed an antidote to his fatal lead poisoning, but thought it best to keep it a secret in case it failed. Unable to resist the joke, though, the two of them concocted a fictitious identity for him to see whether or not he could join incognito.

After a final trip to the Phantom Zone to bid farewell to its criminal inhabitants, Mon-El joins the Legion permanently.