Crawling Monster?

[MegaScience]

This depends on how much you want it. Enemy AI is generally closed source, and I'm not sure what information you can customize would get you precisely. Not to mention the task of making such a model, which would be quite the learning process. I had a class in school for modeling, and I'm still not sure after the whole thing. Also, you can not make them crawl on walls and ceilings. Might not be worth all the effort.