Name: HYDRA
Other Names: the Hydra gang
Classification:
villains
group
Publisher(s): 
First Appearance: Batman (vol. 1) #167 (Nov. 1964): "Zero Hour for Earth!"
Creators: Bill Finger, Sheldon Moldoff, Joe Giella
Number of Appearances: 1
Enemy of: Batman, Robin, Interpol
Type of Organization/Group: criminal
Note: international crime cartel
The narrative caption on the page 1 splash page in Batman #167 introduced the DC Comics version of Hydra: "The entire world knew that Batman and Robin had challenged the might of the international crime cartel called HYDRA! The entire world knew that HYDRA hoodlums waited in shadowy places for the caped crime-fighters who relentlessly moved against them! But what the world did not know was that while battling HYRDA, the dynamic duo was secretly thousands of miles away on another mission -- a mission so vital that if they failed, it could mean Zero Hour for Earth!"
We have seen "Hydra" spelled using traditional capitalization for a proper name as well as in all caps ("HYDRA"), as if it were an abbreviation.
It is worthing noting that Hydra (or "HYDRA") is much better known as a nefarious international criminal organization in Marel Comics, not DC Comics. The Hydra organization introduced in Batman #167 never went on to amount to much, but Hydra over at Marvel is one of the most important and most commonly recurring criminal organizations on Marvel Earth. Marvel's HYDRA debuted in in Strange Tales #135 (Aug. 1965), which means it actually appeared about a year after DC's Hydra (Nov. 1964).
Batman (vol. 1) #167 (Nov. 1964): "Zero Hour for Earth!"
Suggested links for further research about this character:
- http://www.captaincomics.us/index.php?option=com_content&task=view&id=296&Itemid=1
- https://www.comics.org/issue/18723/
- http://comicbookdb.com/issue.php?ID=45061