ef_ring;
Returns: N/A.
This constant is for use in the functions effect_create_above and
effect_create_below, and
will create a ring effect as illustrated in the image below:

if mouse_check_button_pressed(mb_left)
   {
   effect_create_below(ef_ring, mouse_x, mouse_y, 1,
c_aqua);
   }
The above code will create a light blue ring effect below the mouse cursor when the left button is pressed.