An animal that fits the description of having eight legs, horns, and a long tail is the "demon," commonly depicted in folklore and mythology. However, in the realm of real animals, there isn't a specific creature that perfectly matches all these traits. Some fictional or mythological creatures may exhibit such features, but they aren't classified in the animal kingdom.
This description does not match any known animal.
Faun
A mouse on vacation
a kudu has curley horns and a big long tail mesuring 31 cm long and a stripy black and brown body and very, very small legs! funny isnt it
monkey=mono
The fictional animal "Mermaid" is not real They are reputed to have legs on land but when they get wet their legs become a tail like a Dolphin.
A grasshopper
The guinea pig, I have one so I know, Doesn't have a tail.
Four hooves, four legs, one tail, one head, two horns, and usually a goatee.
The species with long tail, eyelids, and four sprawling legs is a lizard.
Why the Swallow Has the Tail with Little Horns was created in 1967.
Gnu: noun: large African antelope having a head with horns like an ox and a long tufted tail