greetings from the future

This is the thing that keeps me up at night presently. How big can you make a Teleidescope? What would you do with it then? Could it crush you?
Take a look here:
Teleidegun!!
Teleidegun??

Just a really big teleidoscope, which is an open ended kaleidoscope - made to look sort of like a giant cannon. But it shoots rainbows, or something like that. Maybe now it will turn out more like a ray gun. You know, the kind they use in outer space. I still keep myself up at night thinking about the final appearance of it....