The Video Hecker is a simple stupid device that can be used to glitchily(?) transition between two composite video signals. As you can see from the schematic, it's literally just three RCA jacks connected to each pin of a potentiometer with their grounds tied together. I'm guessing you need to have an analog TV that's ok with accepting messed up signals in order to use this, like the Commodore monitor I use for most analog video stuff.
The case is just a simple 3D printed design with a huge knob on top for video-hecking precision.
Solidworks models of case
STL models of case