Please forgive my art. I have not actively drawn by hand since the mid 90s. (and my poor paint shop skills at coloring in the scanned in image.)
I have not run DnD for years and like I have mentioned before am converting Carcosa to a home brew system. I will be providing some simple stats for someone to work with for ODnD since most of the people who play in the Carcosa setting will most likely be using those rules.
Armor Class: 5 
Hit Dice: 3-4
Attack: bite (1D8) or claw (1D6)
The Goar appear to be evolved from synapsids. It shares reptilian and mammal traits.
It has a reptilian body, rodent like incisors, boar like tusks and horns like a goat.(plus a few other smaller horns) They also have tufts of thick fur on their chins. Some villagers have domesticated Goars as riding animals. They can move rather fast when they need to. The illustration only an example. There are many subspecies who possess different patterns and colors. Like rodents, Goars need to gnaw on wood or bones to grind down their incisors. These creatures are omnivores, though prefer meat.