In the late '70s, Dave Garcia was in an art class, and made an oil painting of a panda. He promised it to his girlfriend, Monica Sharp, but it ended up being bought at the school art show, so he promised to make her another. In 1981 he delivered a painting of a panda dressed like a samurai, and that original art became the cover of Chronicles of Panda Khan #1:
Here, from a promotional T-shirt, is how he was drawn in the book:
Here's the design and final product (and why not, the info from the back of the card) for the 1990 action figure:
Birthplace: A small out of the way dimension
Height: 8'
Weight: 350 lbs. (that includes all his fur)
Pet Peeve: People who say, "Who gave you the black eyes?"
Favorite Battle Hold: Bear hug
DescriptionDescended from giant mutant Earth pandas, a thousand years in the future, Panda Khan is the Samurai ruler of a genetically improved tribe of battlin' bears. Leaving his alien world in search of great adventure, Khan boarded a Tong pirate ship and using the ancient art of Ting Zing Pao, time-traveled to Earth, 1990. Landing in the sewers, Panda Khan linked up with the Turtles for an unbearably good time. Living by the code of the Khan, Panda Khan "Khantinues" to help the Turtles combat crime and cruelty wherever he finds it. Outfitted with his protective chain mail and samurai armor, Panda Khan's hard for the Foot Clan to "bear."
(There was a later comic that implied that story was canon, for what it's worth.)
And now Gaelstone Media's turnaround for their proposed animated series:
It's not hard at all to see where the NECA action figure's influences lie. Also, Gaelstone also has designs for a Samurai Armor Panda Khan, so don't be too surprised if NECA has another figure on the way soon.