Funny, but probably fictional.
Electric fencers use a capacitor to build a charge (~6000 volts) and release it into the fence. As the charge pulses about once /second (depending upon the make of charger), your reaction is to let go RFN.
I admit I did however, yelp like a dog when I completed the circuit between the wire at the corner of the barn and the new 1/4 mile section I was about to hook up.
I'm more careful about double-checking to ensure the fencer is unplugged now.
Les