In japanese mythology Jorōgumo (絡新婦) is a 400 years old demonic spider that can change its appearance into that of a seductive woman. Generally, in all mythologies the most evil and deadly demons are depicted as women. Thank you sexists!
What if your reflection is not actually you, but in fact it’s a demonic creature watching and waiting. Each time you visit the mirror it get’s stronger, it learns better how to mimic you, how to be you. When it’s ready it will emerge from the mirror devou