Mr. Friendly (or just Friendly) is a pretty complete model. I don't know much about him but people say that he was a scavenger on Xen and that he would neigh if an enemy came by. Some people also think he would have helped you or be a friendly alien (Hence the name Mr. Friendly).

friendly.jpg (5460 bytes) Here is an extremely old pic of Mr. Friendly which is different from the one in the pak file