Each day in June you'll get an entry showing you the first appearance of seemingly minor characters, phrases, objects or events that later became notable parts of comic book lore. Not major stuff like "the first appearance of Superman," but rather, "the first time someone said, 'Avengers Assemble!'" or "the first appearance of Batman's giant penny" or "the first appearance of Alfred Pennyworth" or "the first time Spider-Man's face was shown half-Spidey/half-Peter." Stuff like that. Here is an archive of what I've featured so far.
Today is a day of Martian Manhunter firsts!!
First Appearance of Martian Manhunter as a traditional superhero
During his first four years of publication, J'onn J'onnz, the Manhunter from Mars was basically a traditional crime-solver who just happened to have powers because he was secretly an alien. Secret was the operative term - he would use his powers while invisible so that no one knew that an alien was walking amongst them. That changed in 1959's Detective Comics #273 when another Martian came to Earth...
After determining that he is a criminal, J'onn challenges him (but a problem arises)...
So what is more important to J'onn? Helping others or his low profile? Obviously, the former!!
You gotta love that it never occurs to J'onn that could be his way off of Earth.
Also, I think John was too coy at the end. He should have gotten progressively less vague. "In fact, Chief, you could say that 'we are the same person'" and then try to play it off like a joke.
Luckily for J'onn, by the way, he began a superhero at JUST the right time, 1959. A year later, the Justice League of America was formed. If J'onn was still acting as a cop with powers, perhaps he would not have become a charter member of the Justice League!_________________________________________________________________________________
First mention of the Martian god H'ronmeer
Interestingly enough, it was not until 1986 that J'onn first mentioned H'ronmeer, in Justice League of America #256.
It just so happened that the great J.M. DeMatteis later scripted all of J'onn's appearances in Justice League International as well as writing the Martian Manhunter mini-series (which featured H'ronmeer) so the Martian god was quickly accepted as just part of Martian Manhunter lore._________________________________________________________________________________
First mention of J'onn's love of Oreos
It happened in 1987's Justice League International #8 (yes, the same issue that had the first "Bwah ha ha!")...
Feel free to send in ideas for future debuts I should feature here to firstname.lastname@example.org!