Even though this is the most extreme example I have run into so far, this is called a “witches bend” chimney. The thought is that witches aren’t able to fly down a chimney with a bend in it. Presumably, it was very effective. The question really is this: After over 125 years in this state, is this chimney structurally stable? Fortunately, I didn’t need to evaluate it because the homeowner is going to demolish and re-purpose the bricks to this that has been many years out of service.
Witches Bend Chimney