If you want to try that, you have to add a resistor between one electrode of the zapper and the coil (i would add a 2000Ohms = 2kOhms), else this may damage the zapper because comparing to a human body which has approximately 2000Ohms of resistance with wet electrodes (put on the palms of the hands or on the soles of the feet) the coil has probably only a few ohms of resistance, so the intensity circulating will be too high and the zapper may be damaged.
Also be careful because a magnetic field can penetrate easily inside the body and we don't know what are the effects. (from my experiments i have noticed a rise in blood pressure, which is not good)