Matagot

A Matagot or mandagot is, according to some oral traditions of southern France, a spirit under the form of an animal, mostly undetermined, frequently a black cat, but rat, fox, dog or cow types are said to exist too. Matagots are generally evil, but some may prove helpful, like the "magician cat" said to bring wealth into a home if it is well fed. Traditionally, a wealth-bringing matagot must be lured with a fresh, plump chicken, then carried home by its new owner without the human once looking back. If the cat is given the first mouthful of food and drink at every meal, it will repay its owner with a solid gold coin each morning. In Gascony traditions, you must not keep the matagot all your life long: if the owner is dying, he will suffer a long agony, as long as he doesn't free the matagot.^[1]

Etymology

The word Matagot is derived from the Spanish mata-gothos, from matar (to kill) and gothos (Goths).^[2] The Germanic Goth tribes settled in Spain, Southern France and Italy and eventually converted to Christianity, so Goth means "Christian" in opposition with Moro which means "Muslim". Hence a matagot would be an evil spirit who kills Christians.

Another form is magot, and this word designs a bunch of money, a treasure, so the people who became rich were supposed to have a "magot" in their home.

References

1. ^ Bladé, Jean-François (1886). Contes de Gascogne. Paris: Maisonneuve. 
2. ^ Masse, Michel (1842). Mémoire sur le canton de La Ciotat. Paris.