What is the origin of the 12-foot-tall mummy of a two-headed being, known as Kap Dwa that was reportedly unearthed in Patagonia?

This is an interesting situation. This, in fact, is an extraterrestrial experiment in genetic manipulation and was done to create a kind of warrior being for purposes of manipulating humans. So this is a genetically engineered Anunnaki/human hybrid, not a true Anunnaki but incorporating more of the Anunnaki genome, particularly conferring large stature. The two-headed configuration was instilled genetically for shock value. So what you find in this mummy was a surviving prototype. It is a failed experiment because the two-headed configuration resulted in a being more difficult to train and keep organized for a purposeful action through a manipulation given externally, and proved, in the end, to be more trouble than it was worth, so the idea was abandoned.