Shocking is an interesting qualifier; because one thing colour cannot do is shock in the way electricity or collision can. Extremities of touch (as with a blow), of taste (chilli, acid), of smell (sal volatile), of sound (earsplitting din, the Panic shout) ... all of these can, of course, be literally intolerable. As for sight, well the photoreceptive layer of the retina is divided into rods and cones. Rods are easily overstimulated by illumination--the intense glare of light that blinds--but cones, responsible for colour vision, do not seem to work this way. In a normal eye, there is no intensity of colour (as opposed to of brightness) that is actively painful, or intolerable, after the fashion of these other things. Since colour is indeed perceived in terms of varying intensities, it is very strange that the intensity doesn't seem to have an upper level.
Is this the only portion of the human sensorium that works this way?