Raw Nerve

When a living creature is killed by massive amounts of electricity (such as by being struck by lightning or subjected to a magical attack), their dying terror sometimes causes their soul to linger on the Material Plane. Necromantic energy takes hold of their brain and nervous system, causing these organs to burst forth from the charred flesh and become a raw nerve. These horrific undead float a few inches off the ground in a macabre arrangement morbidly parodying the creature's living form, with its brain at the top and nerves dangling below, crackling with electrical energy.

A raw nerve can sense the thoughts of the living, perceiving them as a chaotic jumble that evokes an uncontrollable rage. The undead seeks to destroy the sources of these thoughts, which often means killing every living creature it can sense. Once a raw nerve detects no more thoughts, it grows still, floating in an almost meditative state. However, its fury instantly reawakens should a thinking creature pass too close. Though it's not mindless, a raw nerve can't be reasoned with, and the only way to stop one is to destroy it.