I became aware of this issue like 10 years ago when I stumbled across a mod that attempted to fix this, but unfortunately it only included 2 tails for the adult horses so I decided to make my own (yes this is one of my first mods ever dating back to 2011) WHAT HAS BEEN CHANGED This is an actual issue caused by their tails which for some reason enable the specular shininess on the entire horse's body resulting in this silly issue. Have you ever noticed that your horses look like they were dipped in water or made out of metal especially during nightime? Well if you did don't worry, you are not going crazy!