Tales of the Legion of Super-Heroes in "The Doom of the Super-Heroes"
*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 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, Mister 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. *Source: The Official Legion of Super-Heroes Index #2 - Published by ICG.
"A Tree Grows on Second Street"
An untitled Little Pete strip.
Superboy in "When Krypto Was Superboy's Master"
Superboy and Krypto pretend to exchange minds in order to teach a cynic a lesson.