OMG this is TFF.
Have a cat that won’t stay off your counters? I do. I finally got fed up with it enough to do something about it: scare the crap out of him with a motion-detecting blender (while recording the results for my own amusement, of course).
How-I-did-it instructions are included in the link.
Of course, we now have empirical evidence that the number of times you must scare the crap out of a cat in order to modify its behavior is a minimum of 4.
Wouldn’t be science without data.