Superboy in "The 5th Dimensional High School"
Mister Mxyzptlk hopes to win honors in his practical jokes class, by tricking Superboy and Lana Lang into the 5th dimension.
An untitled Casey the Cop strip.
Tales of the Legion of Super-Heroes in "The Legion of Substitute Heroes"
*Five rejected Legion applicants - Polar Boy, Night Girl, Stone Boy, Fire Lad, and Chlorophyll Kid - refuse to resign themselves to failure, and band together as the Legion of Substitute Heroes, secret pinch-hitters for the real Legion. Together they build and equip a mountain headquarters, and keep tabs on their heroes. However, discouragement soon sets in as they find the Legionnaires completely handling any and all threats to Earth.
Eventually, though, when the Legion leaves the planet to combat a fleet of attacking robot ships, the Substitutes discover that these ships are merely a diversion and uncover a plot by the malevolent Plant Men to take over the Earth. Traveling to their home planet, the Substitutes thwart the Plant Men's scheme, and return to Earth as secret heroes. *Source: The Official Legion of Super-Heroes Index #2 - Published by ICG.
(1st Chronological Appearance of the Legion of Substitute Heroes; 1st Chronological Appearance of Stone Boy, Polar Boy, Night Girl, Fire Lad, and Chlorophyll Kid).