Centaur

Centaurs are misshapen, mutated creatures. They are a by-product of the Forced Evolutionary Virus, and some of them were created by the Master by tossing a varied mix of humans, dogs and other animals into an FEV vat and seeing what came out the other end. As a result, they can differ quite a lot from one another.

The Centaurs are not only created by the FEV, they also seem to live in a heavily irradiated environment.

West Coast
In the Core Region, centaurs are created by the Master and frequently travel in packs with floaters. They encompassed a large bulk of the Master's armies and are commonly found with the nightkin and other remnants of the Master's army who roam Northern California.

Capital Wasteland
The Centaurs encountered in the Capital Wasteland are physically different from the Centaurs from the Core Region, trading the dog-like head for a human one and the feelers on the back for 3 long, tentacle like tongues. Like their western counterparts, they are created by FEV along with the Super Mutants, so their birthplace is Vault 87. Unlike its core region "cousins", the Capital Wasteland Centaur uses a ranged attack: a high-arcing, slow-moving projectile that can carry lethal doses of radiation. Oddly enough, it is capable of igniting lingering gas vapors as well, indicating some kind of pyrophoric quality. Centaurs are known to accompany Super Mutants as "guard dogs", so if you see one, expect super mutants ahead.

Fallout 3
Centaurs can pose a moderate danger to low level players but they move slowly. They have long, tentacle-like tongues which can be targeted in V.A.T.S. making them easier to deal with. Usually they don't carry anything on them, although occasionally they sometimes carry chems like Jet or a small amount of caps. When meeting one in the Capital Wasteland it will spit radioactive balls at you, which can hit you succesfully from medium to very long ranges. The damage done by the spit is relatively low, but can increase your rads rather quickly. Thankfully the spit is slow moving and can be dodged with relative ease. When up close, the Centaur whips its tongue at you (as a mean of melee attack). Luckily, the Centaur's melee attack is rather delayed and a quick melee will often hit it. However, Centaurs are rarely found wandering around alone and serve as indication that Super Mutants may be nearby.

Appearances
Centaurs appear in Fallout, Fallout 2 and Fallout 3.