Centaurs encountered in the Core Region and Mojave Wasteland were created by the Master. The creation process involved tossing a varied mix of humans, dogs, and other types of animals into a Forced Evolutionary Virus (FEV) vat to be infected by the virus, and then seeing what mutant chimera emerged as the virus produced rapid and unpredictable mutations. The resultant centaurs can differ quite radically in physical appearance from one another. However, all known centaurs are somewhat humanoid in appearance.
Physically, these centaurs are around the size of a bear, with a large, misshapen torso and six humanoid arms that serve as legs. A cluster of wriggling fleshy tentacles bloom out from their underside, scrabbling at the ground around them. Branching from their front halves are a pair of long, thick necks, with a canine head on the left and a humanoid one on the right. The canine head has a thick metal collar around its neck, adorned with spikes, not unlike an ordinary dog collar. The two heads are seemingly aware that they are separate creatures, as the dog head can be seen trying to gnaw on the humanoid head.
So far, the two-headed centaurs have only been encountered on the West Coast, in the Core Region.
In this type of centaur, only the human-like head remains, and the feelers on the back are replaced by three long, tentacle-like tongues. Unlike its two-headed "cousins", this kind of centaur uses a ranged attack: a high-arcing, slow-moving saliva projectile that can carry lethal doses of radiation. Oddly enough, it is capable of igniting lingering gas vapors as well. In close quarters, it utilizes a long, three-pronged tongue to whip and slash at any intruders.
This kind of centaur can be encountered both in the West and the East of the former United States.
As the name suggests, they are a bigger and stronger variant of a centaur. Having been exposed to much more radiation than regular centaurs, they have significantly more muscle mass as well as thick clusters of tumors growing from their backs.