putting a white mesh grill in the bumper and putting a 12 black light infront of it so all you'd see is the grill glowing? probably get a ticket though right?
if any spoofy lights (neons etc.) are visible to other drivers when you are moving/driving --> illegal and you will get pulled over, might get a ticket or a warning.
its concidered "unauthorized lighting" in most states, im not sure about each state in paticular but ive been around and ive gotten a few tickets for that