Mirror.

You thought you were going crazy. It all started with a small thing. First, you saw that your reflection in the mirror blinked a second later than you, but you ignored it. Then it became more late, more noticeable.

One day, standing in the fitting room, you were spinning around, looking at the clothes you had chosen, and when you raised your hand, the reflection was very late, you noticed this, leaned over, and in the mirror you were standing straight. You took your phone and started filming it, but on video everything was done without delay, you blamed it on fatigue. But that same day, in the evening, when you were washing your face, your reflection did not move at all and simply looked at you emotionlessly. From that day on, you covered all the mirrors in the house.

That night, you woke up from a rustling sound, as if something had fallen in the room... maybe fabric? You immediately realized that it had fallen from the mirror, you did not get up, you lay there all night until dawn. When the sun rose, you got up too. Approaching the mirror, you noticed that this fabric was lying on the floor, and looking closer, you saw the inscription on it: "I missed you." Your gaze immediately moved to the reflection - there stood "you", but in a different pose, and instead of fear on the face there was a light, satisfied smile.