The mutant superhero Captain Comet returned in Strange Adventures 11 (Aug. 1951) for his third appearance, but second adventure.
Titled The Day the Past Came Back, this story by writer John Broome and artist Carmine Infantino starts by pitting this transitional superhero figure against one of my favorite foes, a Tyrannosaurus rex (this one revived from a skeleton in the Midwest City Museum Hall of Fossils).
Luckily, librarian Adam Blake is nearby. Wading into the action while museum patrons panic, the Man of Destiny uses superhuman strength to handily hurl away the dinosaur. But he learns that Capitol City (apparently Washington, D.C.) is overrun by brontosauruses, pterodactyls, devolved humans and other prehistoric menaces, thanks to an evolution reverser ray invented by Dr. Alex Philador, who has decided humanity is evil and requires a reboot.
The tale anticipates DC’s Silver Age gorilla fetish as Comet himself is devolved into an ape. But the simian superhero, retaining his advanced intelligence, surprises Philador and saves the day. The exploit ends with the humble librarian asking his coworker Miss Torrence to tell jim just how wonderful Captain Comet is.
The increasingly streamlined art and the science fictional themes pointed directly at the superheroic ingredients that would converge to spark the Silver Age of Comics five years later, in Showcase 4 (Sept.-Oct. 1956).