Tommy Tyme was the scrappiest of those heroes.
First appearing in Young Allies #7, Tommy was just an average Brooklynite who found a genie in a pond and wished for help with school (this according to Jess Nevins and Ronald Byrd). His wish was granted permanently with the “Clock of Ages.” This powerful device can take Tommy to any time period (and apparently translate the local language for him) allowing him to learn about (and interfere with) history.
After his initial run-ins with Robin Hood, Benjamin Franklin, Attila the Hun, Horatius at the Bridge, and Merlin (shown at left), Tommy went to one of the most popular time periods in Marvel history: ancient Egypt.
Around roughly the same time as the unintentional crossover between the Fantastic Four, Doctor Strange, the West Coast Avengers and Apocalypse fought Rama-Tut (the artist later known as Kang the Conqueror), Tommy went back to learn about Pharaoh Khufu and the great Pyramid of Cheops.
In Young Allies #12 (Spring 1944) Tommy begins his adventures as he normally does – showing frustration with his history assignment. Turning to his trusty Clock, Tommy sets the dial back to investigate pyramid-building firsthand.
As soon as he arrives, Tommy finds himself sold from a slave-trader named Hola to a taskmaster named Phao. He tries to free himself with his trusty slingshot, but he’s captured quickly enough and other slaves tell him to go along with it for his own safety. After helping place the last stone on top, Tommy insights a slave revolt rather than build another pyramid. His fighting skills are enough to help the slaves reach freedom but not enough to free himself. Phao decides to punish Tommy by entombing him alive, thus teaching Tommy why the pyramids were made.
“Well, of all de silly things! Ya mean ya built dis great big stone pyramid just to bury one little dead body in it? Crazy, dot’s wot it is!”
Learning what he came to learn, Tommy single-handedly defeats three Egyptian slave-masters, locks them away in the tomb and returns to class to answer the teacher’s question (and mention how extra bodies should be found in the sargophagus.
Costumed in his red sweater, blue pants, matching blue suspenders and black bowler hat, Tommy doesn’t look like a typical super-hero, but with his amazing fighting skills (particularly with his slingshot) and the Clock of Ages, he’s a match for any time-traveler.
He also made a lot of allies in his more than 20 appearances. As mentioned earlier, he teamed up with Merlin and Robin Hood, both immortals in the Marvel universe, and he was responsible for one of Hercules’s most famous victories.
Why hasn’t the character shown up again?
Boy heroes, especially those without costumes, were out of vogue at Marvel for many years. The theory goes that 1940s comic book creators put children in stories to give young readers someone to identify with, but by the Silver Age, readers were expected to associate with any type of hero, and heroes that needed a parent’s permission to fight crime after bedtime didn’t seem all that exciting.
How could the character be brought back?
As far as a time-travelling do-gooder goes, there are too many to reference. It should be mentioned that Marvel has agencies that recruit such individuals as operatives in the timestream.