I'm trying to identify a story I read ages ago in a science fiction anthology.
A man possesses a "box" that appears to transport objects to another dimension. He steals some object of value and hides it by putting it into the box, where through some distorting affect it now appears tiny and differently shaped. When he checks on it later a small mishappen being seems about to steal the item. He reaches in and crushes the tiny being. Sometime later he enters a room and sees the valued object sitting on the floor. He goes to pick it up and a giant distorted hand reaches down and crushes him. He has reached into the future and killed himself.
Sound familiar to anyone?