The Shocker

 is a unique variant of the Power Fist with an electric element added to increase its effectiveness against robotic enemies.

Characteristics
The Shocker is an Unarmed Weapon and its damage is affected by the Iron Fist Perk. It is especially effective in combat against mechanical and robotic enemies, dealing a considerably higher amount of damage, than otherwise. It also happens to leave an 'aftershock' effect upon robotic enemies (though, it may possibly occur on other types.), similar to the ones left by Pulse Grenades and Pulse Mines, the Tesla Cannon, Jingwei's Shock Sword, and other shocking weapons, likely the reason for the namesake.

Location
The Shocker is found, complete with holotaped instructions, in the Flooded Metro near Arlington Library.

YouTube Videos
Obtaining The Shocker sG3r1Z7TbbE