Comic Title: Adventure Comics #310
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: July 1963
On Sale Date: May 29, 1963 Copyright Date May 29, 1963
Source: Library of Congress, Periodicals 1963

Frequency: Monthly
Cover Price: $0.12
Page Count: 32
Editor: Mort Weisinger

Title: "The Doom of the Super-Heroes"
Pages: 17

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

Writer: Edmond Hamilton
Artist: John Forte

Reprinted In:
Adventure Comics #500 (1983)
Legion of Super-Heroes Archives Vol. 2 HC (1992)
Showcase Presents:Legion of Super-Heroes Vol. 1 TPB (2007)
Legion of Super-Heroes:The Silver Age Omnibus Vol. 1 HC (2017)
Legion of Super-Heroes:The Silver Age Vol. 1 TPB (2018)

Feature Character(s)

• Legion of Super-Heroes (last appearance in Adventure Comics #309; next appearance in Adventure Comics #311)
• Cosmic Boy (last appearance in Adventure Comics #308; next appearance in Adventure Comics #311)
• Saturn Girl (last appearance in Adventure Comics #309; next appearance in Adventure Comics #311)
• Chameleon Boy (last appearance in Adventure Comics #309; next appearance in Adventure Comics #311)
• Sun Boy (last appearance in Adventure Comics #309; next appearance in Adventure Comics #311)
• Bouncing Boy (last appearance in Adventure Comics #309; next appearance in Adventure Comics #311)
• Invisible Kid (last appearance in Adventure Comics #307; next appearance in Adventure Comics #314)
• Shrinking Violet (last appearance in Adventure Comics #308; next appearance in Adventure Comics #313)
• Superboy (last appearance in Superboy #106; next appearance in Adventure Comics #310)
• Ultra Boy (last appearance in Adventure Comics #309; next appearance in Adventure Comics #314)
• Mon-El (last appearance in Adventure Comics #309; next appearance in Adventure Comics #312)
• Lightning Lass (last appearance in Adventure Comics #308; next appearance in Adventure Comics #312)
• Triplicate Girl (behind-the-scenes; last appearance in Adventure Comics #308; next appearance in Adventure Comics #313)
• Phantom Girl (behind-the-scenes; last appearance in Adventure Comics #304; next appearance in Adventure Comics #313)
• Colossal Boy (last appearance in Adventure Comics #309; next appearance in Adventure Comics #313)
• Brainiac 5 (last appearance in Adventure Comics #309; next appearance in Adventure Comics #311)
• Element Lad (behind-the-scenes; last appearance in Superman's Pal, Jimmy Olsen #70; next appearance in Adventure Comics #316)

Villain(s)

• Mask Man (the 30th century descendant of Mr. Mxyzptlk; no further appearances)

Other Character(s)

• An unnamed science police offficer (no further appearances)
• Ak Aru (a scientist on Doll World; no further appearances)
• An unnamed female inhabitant of Doll World (no further appearances)

Cameo Appearance(s)

• Star Boy (as a face on splash page)

Comments:
Part 2: "Last Stand of the Legion"

The Legion Pledge is first depicted in this story.

Synopsis:
On the day of the Legion’s Rededication Ceremony, a doll-sized lead-masked villain, possessing the powers of all the Legionnaires, appears over Metropolis, kills Ultra Boy, and vanishes. The heroes, calling this nemesis "Mask Man", surmise that someone so small could only have come from the Doll World, and track him there, only to watch as he murders several more Legionnaires.

Retreating to a nearby planetoid, the Legion builds a defensive citadel. However, Mask Man soon infiltrates the stronghold, eventually killing every remaining hero except Superboy, who guesses that their foe is actually a descendant of his 5th-dimensional foe, Mr. Mxyzptlk. Once the Boy of Steel tricks him into saying his name backwards, Mask Man is banished to his home dimension. All of the effects of his magic vanish, the Legionnaires return to life, and only Superboy is left to remember the last stand of the Legion.