I made this so people may have a look at how the Aliens act as enemies (you have to be a non-xenomorph race for them to attack you.). 

This plugin places several hostile Alien Drones in Vindasel, the same Dungeon Umbra is in (it's south-west of the Imperial City. If you can't find it take a look here: http://www.uesp.net/maps/obmap/obmap.shtml?centeron=Vindasel&). Be prepared! They come range from level 1-15, come alone and in groups and they will destroy you, if your character is low-level. Some detect-life, light or night-eye spells are advised, as are fire-based weapons and/or spells. 

I went in there with an everage level 18 character wearing complete daedric equipment ,with no mods activated, except for XenomorphRace.esm, XenomorphIncreasedHtH_150.esp, and this plugin. I got my ass kicked.