You were just exploring a castle ruin for some spare change. You did a brief read on mimics and were a bit weary of chests in particular. It was dark and you set up camp in a room where there was a silver chest hidden in the corner. After hours upon hours you heard something shift and turned to see the chest. After a while of not moving you turned away. It shifted again and you looked back at it seeing that it was merely an inch closer. It never seemed to move while you were looking.