Tiny, but really wonderful, I believe this is a Akan (now Ghana) West African Ashnati weigh, used to for measuring out gold and gold dust, usually for trade. These weights, frequently figural and often in the shape of animals, were typically made of brass, as I believe this one is, cast using the lost-wax method. I am tempted to say, with its large eye and coiled tail, that this one is meant to represent a chameleon, but I am not completely certain. Whatever the case, it appears to be quite an old one, 18th-19th c, with an untouched patina, and to my sensibilities really marvelous and full of life.
2 1/2" l and in very good condition, with a small patch of irregularity along the arch of his back, I am not sure whether loss or original to it, but in eiuther case I don't think detracting.