Feral ghoul

Feral ghouls or mindless ghouls are those ghouls (humans mutated by radiation) that lost their minds and became aggressive animals. Their minds are almost completely gone and they react mostly on instinct.

Feral Glowing Ghouls
Some of the Glowing Ones also become feral (or some of the feral ghouls start to glow due to exposure to radiation). They are known to use radiation-based attacks on humans.

Endless Walkers
Endless Walk is the punishment in which a ghoul from the Reservation is stripped of every worldly possession, including clothing, and sent marching into the wasteland. No ghoul has ever come back from the Endless Walk (exiled from the Reservation Otto Stead was saved by governor Dodge at Hoover Dam).

Not all Endless Walkers end up scorpion food, at least not at first. On those rare occasions when one survives more than one year in the wasteland, they turn into wandering, voracious creatures on an endless quest for flesh. Due to their prolonged, open exposure to the desert sun, high radiation, and other hardships of the wasteland, these unfortunate ghouls, who were banished, naked, from the Reservation, look like walking, sun bleached chunks of beef jerky. Their constant exposure to the hot sun and high levels of radiation has caused their skin to toughen into natural, hardened leather, but at the same time, their brain has completely cooked.

Endless Walkers who have been in the wastes for so long become a creature of instinct and will attack anything that moves in a vain effort to quench an appetite that can never be quenched. Also, their skin is very tough and they strike with their claw-like hands with surprising quickness. Fortunately, endless walkers do not travel in groups. In fact, it is a rare occasion when someone comes across one, though most who travel this side of the wasteland like to keep their distance from the voracious creatures. Though encounters with Endless Walkers are rare, when someone does encounter them, they are assured to never forget the encounter, if they survive.

Appearances
Feral ghouls appear in Fallout (in random encounters, as "mindless ghouls"), Fallout 2 (as "ghoul crazies") and Fallout 3.