I decided to make a ray gun. But it had to actually be a ray gun, not something that looks like a ray gun but doesn't do anything. Given the only technology we actually have today that come close to science fiction ray guns is a laser it had to be a laser. I started with this image:
Just the laser itself was not enough so I added a little peizo oscillator (the black bit on the top and inside the handle is a Teensy which drives it to make an interesting noise when the laser lights up. There is a battery in the handle as well. It is about 5 inches long (similar enough to the Derringer) and should fir discretely into a pocket or a purse. Mrs gets to wield this thing (I have the vortex manipulator).
Programming the Teensy to drive the oscillator was interesting. The oscillator is a very simple thing, it can only play one note at a time, no chords. But I can send any note by frequency and control the timing etc. I can make it play a tune if I want, in this case it make a buzzy sort of noise which seems appropriate.