So technically the code for the behemoth IS actually in the game right now, just looking at the entityclasses.xml file. It likely just never gets called on in any of the spawning groups in "vanilla" A16x. Saying that the behemoth is in the game at the moment isn't technically a lie, but saying that the game or the xml files aren't edited whatsoever would be a little irresponsible. Is there any chance that video was a replay of a live stream? I haven't watched the full video yet but Id like to believe someone would have mentioned tweaking the files, especially because it is so easy to "CYA" and tell accurate information that I don't see why anyone would opt not to do so.