Tahra puts forth an idea.
I can be a witch with my cauldron. Somebody can be an orc. I can tell the orc he can be a great ruler, make all fear him if only he will swear fealty to the great God Mumbo-Jumbo, Patron of those who want to do whatever they want. The orc could see thought the plot. Hmm. won't work with just one; probably would work better if a companion of the orc fell into the trap.
https://www.phrases.org.uk/meanings/mumbo-jumbo.html There's also a racist poem The Congo Vachel Lindsey (who was anti-racist)
The phrase probably originated from the Mandingo name Maamajomboo, which was a masked dancer that took part in religious ceremonies. In the 18th century Mumbo-jumbo referred to a West African god.
Francis Moore, in his 1738 work Travels into the inland parts of Africa noted:
"The women are kept in the greatest subjection; and the men, to render their power as compleat as possible, influence their wives to give them an unlimited obedience, by all the force of fear and terror. For this purpose the Mundingoes have a kind of image eight or nine feet high, made of the bark of trees, dressed in a long coat, and crowned with a whisp of straw. This is called a Mumbo Jumbo; and whenever the men have any dispute with the women, this is sent for to determine the contest, which is almost always done in favour of the men. One who is in the secret, conceals himself under the coat, and bringing in the image, is the oracle on these occasions. No one is allowed to come armed into his presence. When the women hear him coming, they run away and hide themselves; but if you are acquainted with the person concealed in the Mumbo Jumbo, he will send them all to come, make them sit down, and afterward either sing or dance, as he pleases; and if any refuse to come, he will send for, and whip them. Whenever any one enters into this society, they swear in the most solemn manner never to divulge the secret to any woman, or to any person that is not entered into it: and to preserve the secret inviolable, no boys are admitted under 16 years of age. The people also swear by the Mumbo Jumbo; and the oath is esteemed irrevocable. There are very few towns of any note that have not one of these objects of terror, to frighten the poor women into obedience."