You know, I think it was a little silly to name an alien species this. It means "alien (foreign) form." Well, duh! But, in this case, we are discussing a very specific alien form, the one designed by H.R. Giger for the Alien film series. Large, black, skeletal, fast, smart, pitiless, with claws, harpoon tail, extending chrome teeth, a bony carapace and concentrated acid for blood, these guys are nasty! And we haven't even gone into their reproductive cycle, which involves infesting a host and then killing it at birth. They grow fast, too. Hive mind, it seems, based on Aliens (my favorite of the movies).
So yeah, these guys are great. And I know there have been several efforts to recreate them without license infringements. My personal favorites in 15mm are the ones done by Khurasan Miniatures under the Space Demon line. Not content with the classic, they have released several variants, including a queen and a giant 'troll' version. Have a few pictures...
The 'regular' Space Demons
The 'troll' - notice the scale comparison.
Oh, and there are bigger ones, too.
H.R. Giger, the Swiss artist who designed the original xenomorph for the film, died earlier this month at the age of 74. His designs continue to inspire and haunt us, and were often based on his night terrors. RIP.