Classification: Cryptid
Originated in Ancient Rome, Pliny the Elder wrote about a curious creature that he had come across. This creature looked just like an elk, except for a few minor differences. One difference was the elk seemed to have no back joints. He theorized that the animal must sleep on its legs or lean against a tree. The second most noticeable difference was that the top lip of the animal was to long for it to graze properly. Instead it had to graze backwards.
This animal most likely was just an elk that was either mutated slightly or sick. It makes me wonder what other problems it may have had in it's poor miserable short life.
Sources: https://en.wikipedia.org/wiki/Achlis, http://itsmth.wikia.com/wiki/Achlis, http://cryptidz.wikia.com/wiki/Achlis,