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.