RTF is a global modification that replaces all towns in the game.

Hmm, interesting... for some reason, I imagined a bone golem in such an exotic form - like Krang from the Teenage Mutant Ninja Turtles, with a skeleton inside the shell, controlling it, but I can't imagine what the shell itself should look like - some kind of ghoul, I don't know...

P.S. and another monster would be cool))) like this - a chain of fused ghouls, like a "caterpillar"... also a very "exotic" look...)))

There are two extremes here:
1) A bone golem is a pile of bones - in terms of creation technology, it's simply a heavier version of a skeleton; it's harder to break, but it's not very agile.
An interesting point is that in this case, the invisible connection between the bones is stronger than the bones themselves; otherwise, there's no point in them - they would fall apart from any blow.
If it's made, it should be based on the model of the Earth Elemental from the fifth game.
2) A necro-dreadnought - a necrolite who has committed a crime is turned into a golem; I imagine this as a seven-headed Earth Elemental with a skull instead of a head, and the body is supported by the magic of the imprisoned lich, but it must definitely be a high-level unit