Electric eels control zombie prey

electric eels zombie prey animals shockElectric eels use their amazing electromagnetic abilities (in water) to not just shock and stun their prey but also to induce electric twitches in the preys muscles. These rapid muscle contractions appear to make the hunted fish 'jump', so revealing its location.

But what is amazing is that the electric eels are controlling the fishes nerves and not the muscles tissue itself directly. The muscle spasms are a result of the fishes nerves being remotely controlled by the electric eels.

Electric eels and preys muscle twitches

electric eels “remotely control” their prey's movements. The electrical discharge causes whole-body contraction and twitch in the prey by affecting motor neurons rather than muscles directly. This first stimulates prey to move and reveal itself and then to freeze, allowing its capture.
The shocking predatory strike of the electric eel

"You and I couldn't activate every muscle in our bodies at once, but the eels can do that [remotely] in their prey.
"They can completely immobilise prey or they can make prey move, depending on what they would like to do."
Electric eels 'remotely control their prey'

Electric eels in water?

How did electric eels evolve this ability to produce electricity in water?
How did electric eels evolve muscles that produce electricity?
How did electric eels know that electromagnetic bolts - doublets - could stun and also control their prey?
Why do electric eels not get shocked by their own electrical pulses?