I like to let links do the talking where possible: http://www.weburbia.com/physics/FTL.html
see 3. Shadows and Light Spots. One point not mentioned there is that the 'spot' won't be a spot for very fast motion of pointer - becoming an increasingly elongated ellipse along the apparent direction of motion. Ellipticity here being ~ (2*1011
) = 666 - basically a faint streak!