Species: Mutated Chimpanzee/Gorilla (see biography)
Other Appearances: Movie novelization by Dean Owen in 1960, published by Monarch; 23 issues of Konga, published by Charlton Comics, and included some issues with art by Steve Ditko; one issue of Fantastic Giants (continuing the numbering from Konga); three-issue "miniseries" by Charlton (The Return of Konga #1, Konga's Revenge #2 and 3); one shot reprint issue in 1968. Some Charlton issues were reprinted in a 2011 trade paperback called Angry Apes n' Leapin' Lizards, while the Ditko issues were reprinted in the 2013 hardcover Steve Ditko's Monsters: Konga.
Merchandising: Other than the comic books and novelization, I haven't discovered any merchandising of Konga, although art from the poster was appropriated for some other movies, especially in Italy!
Biography: Konga was a chimpanzee owned by British botanist Dr. Charles Decker, who injected Konga with a serum that transformed him into a ferocious gorilla-sized ape. Decker, driven insane, hypnotizes Konga to get revenge on his enemies. Later, when Decker tries to make the woman who loved one of his enemies to be his lover, his own current girlfriend gives Konga an extra-large dose, which turns him into a gigantic gorilla, which goes on a rampage. Decker is grabbed by Konga during this rampage, and both are killed by the British army, with Konga reverting to his chimpanzee form on his death.
In the Charlton comic book, Konga has a different origin story given, with the scientist being more sympathetic and his assistant becoming his wife! In the second issue, following the death of the original Konga, friends of the dead scientist (Sandra and Bob) inject another chimp with the serum, creating a second Konga, who went on to have more adventures, including battles with other giant monsters, aliens, mad scientists, giant robots, and more. Bob and Sandra make scattered appearances in the remainder of the series.
Powers: In his gigantic form, Konga had great strength and durability, although he was still vulnerable to bullets; the comic book version was tougher and was never able to be killed.
Miscellaneous: Unlike Kong Kong, the obvious "inspiration" for this movie, Konga was presented as a man in a gorilla costume instead of being portrayed in stop-motion animation. Other movie monsters adapted into comics form by Charlton were Gorgo and Reptilicus, with the former having more success than the latter.