a new flashlight was developed that temporarily blinds, disorients and nauseates. they aren't kidding. it's of course designed for the department of homeland defense. check it out here:

https://www.technologyreview.com/Infotech/19142/?a=f

it ships without a handlebar mount for your bike, but i'm sure you'll manage :-).

It's funny, the flashing light coming from my CatEye OptiCube drives me positively nuts when dusk arrives. Now I know why!

I don't need a light to make people barf, all they have to do is take one look at my face, that usually does it!!