Check out my gay license plate display.
Having seen those displays before, I know that they only come on when the brakes are applied, so I would suggest: "STOP!"
Personally I would not put one of these on my bike as the letters are small so the person behind you will instinctually try to get closer to you at the light to see what it says, which kind of defeats the point.
Having seen those displays before, I know that they only come on when the brakes are applied, so I would suggest: "STOP! HAMMERTIME!"
thats it. thats all."Back off!!"