A symbol of control and lack of control that you have over the small things in life.
The “small” or unimportant things can also mean those that are invisible.
Mice are often “signs of death” (Death is meant in the sense of completion). They are symbols of nagging thoughts and a nagging conscience. When they become a plague, they are a bad omen. In Goethe’s Faust, mice appear in the form of ghosts that nibble at the Pentagram that is supposed to ban the devil. Gray and black mice in a dream point to bad luck.
The gray and the black mouse may also be a symbol of the shadow, since gray and black are shadow colors.
The positive meaning of this symbol lies in the fact that parents sometimes call their children “little mouse.” It is also the language of lovers who use such endearments.”
According to Mohammed, the mouse represents the “little sinner,” the adulteress. When Faust dances with a witch, a mouse jumps out of her mouth. White mice are believed to be the souls of children and of the poor, and also fever demons.
According to Jung, the mouse is the animal of the soul, the image of a difficult-to-understand reality, the relationship of the dreamer to sexuality, fertility, and the devil or witch.
Folklore: Always has an erotic meaning.
The mouse is the penis escaping into the hole.... Little Giant Encyclopedia