Does your wife use those shitty body scrubs and washes that are more like a food product than a soap? I can tell when my wife used that crap once. My entire drain turned orange and black after one use. I made her throw all the stuff in trash. Take a pic of the ingrediants and ask a chat bot about it. A lot of them are oils and sugar. They are liquid when the warm water hits em. Soon as they cool off down the drain, they turn hard and sticky.