mouse droppings

n. [MS-DOS] Pixels (usually single) that are not properly restored when the
mouse pointer moves away from a particular location on the screen, producing
the appearance that the mouse pointer has left droppings behind. The major
causes for this problem are programs that write to the screen memory
corresponding to the mouse pointer's current location without hiding the
mouse pointer first, and mouse drivers that do not quite support the
graphics mode in use.

