Half man half horse Forward half was human down to the waist, rear half was horse from the shoulders down.
The mythological creature was called a centaur
A centaur is a half man/half horse creature found in Greek Mythology.
Half man, half horse specifically the torso, head and arms of a man, attached where the neck of a horse would have been, and the four legs, body and tail of a horse.
The creature that is half man, half horse on the TV show "Hercules" is a centaur. A centaur is a mythical beast from Greek and Roman mythology.
Centaurus
It is called a centaur. If the upper half is human with the lower half horse and the horse section has all four horse legs, it is indeed a centaur. If it has the upper half of a human with the lower half of a horse but only 2 legs like a satyr it is a Sileni. There are also horse-headed men but I can not find the names for them. There is also the deity Hayagriva in Hinduism and Buddhism that has a white horse's head and a human body and is pictured as seated on a lotus.
Mermaids or Mermen
A centaur is a mythological creature with the body, arms, and head of a man, but the front legs, back legs, and body of a horse.
A half horse half man creature is known as a centaur in Greek mythology, typically depicted with the upper body of a human and the lower body of a horse. Centaurs are often seen as symbols of strength, wildness, and duality due to their mixed nature.
I think you're referring to the mythical half-man - half-goat creature called Pan.
Roman Mythological CreaturesHippocampus - is a creature that is half-horse and half-fishUnicorn - is a creature that is a horse with a long twisted hornCentaurs - is a creature that is half man and half horseSirens - is a creature that is half woman and half birdCerberus - is a creature that is a three head dog which has a snake's tailDryads -- tree spiritsFuries -- three female like bird creatures with snakes for hairHarpy - is a winged monster like creature, with the face of woman, and has the body of vultureMinotaur - is a creature that is half bull and half manKeres - 'Hounds of Hades' brought back evil doers for punishment.Fauns or Satyrs - is a creature that is half man and half goatSphinx - is a female creature that has the voice of a human, the head and torso of a woman, the paws of a lion, the body of a dog, a snake like tail and the wings of a bird