Mongo is an enormous 'super ninja,' a being genetically designed to be superior to any natural ninja. He is stronger, faster, and more adept in combat and stealth such that many of his feats go past mere skill and appear physically impossible (including but not limited to: hiding in a hollow tree thinner than he is, discerning the identity of given individuals from afar by scent alone, easily grappling a plane to swing into a truck on the ground, and stealing weapons from a trained ninja before they even notice).
The downsides of Mongo as a sustainable ninja project include the fact that he was given a weak intellect, he was far too expensive to duplicate, and as of recently he has "learned of the preciousness of life."
Due to the law of the Dr. Mcninja universe which demands that the coolest thing always wins, the only one who was able to beat him in a fight until recently was Judy the Gorilla, and only when he armed with a bazooka. Later, during Paleontologists, Politicians and Prologue, Dr. McNinja bested Mongo and Franz Rayner easily due to their repeated prior defeats as villains earlier in the comic.
Mongo wields chainsaw nunchucks.