Alien -> Queen Alien
Facehugger -> Queen Facehugger
Chestbuster -> ...Queen Chestburster?
Back in the '90s, Kenner's first series of Aliens figures was mostly pretty restrained (go home, Bull Alien, you're drunk), but Series 2 went nuts. A Gorilla Alien is still fundamentally an Alien, so much so that NECA can use a lot of extant molds when making one; a fancy new species name doesn't change the body a whole lot, right? Taxonomy doesn't affect physicality.
But something like a Snake Alien is so wild, so out there, that it needs to be new from the ground up. And so this toy is.
Try not too think too much about the logistics
of a facehugger latching onto a snake, but the resultant xenomorph is basically just a head on a tail. It looks more like a typical xeno tail than the 1992 Snake Alien's did, ending in a single spike rather a pair of pincers. The tail is about twice as thick as usual, but that's because it needs to blend into a body, not just stick out the back. Like a cobra, the ribs expand into a large hood, though NECA improved on the old design by putting a small "torso" lump at the center of it (Kenner's just had more vertebral segments leading up to the head).
The head has that typical long dome -
and since the original toyline was based on Aliens, the dome has spikes and ridges rather than being smooth. The old toy had an action feature: slide a lever on top of the head forward and the inner jaw would snap forward, with the two large fangs on the sides swiveling to strike. NECA's doesn't have that feature, but does try gamely to re-create it: like most Aliens, the tongue can extend; unlike most Aliens, doing that takes the lateral fangs with it; also unlike most Aliens, there's a second inner jaw that can come out even farther! Not even the Chrysalis Alien has as much reach as the Snake Alien!
Without a normal body, the Snake Alien can't have normal articulation. The tail is bendy PVC, there's a swivel where it meets the ABS torso, and the head is on a swivel/hinge joint, but that's where it might end... if a company other than NECA was making it. The chin is hinged, to make the bites look fiercer, and the big fangs are swivel/hinges.
But even that's not enough, because the hooked spikes at the ends of the ribs are also articulated, adding a dozen more swivel/hinge joints to the total, and allowing Snake to spread their ribs even wider.
The mouth on my figure is slightly warped, but I couldn't tell that until I'd already opened it - and since the Aliens toys are sold in clamshells, I can't just box it up and take it back. Oh well. The original Kenner version was made from the same translucent green plastic as the Mantis, then given some bronze paint on the back and the head. NECA's isn't translucent, but it maintains the colorscheme, and adds purple on the fangs and rib-hooks.
After testing the waters with the plainer xeno variations, NECA is confident enough to try the wilder takes. Snake Alien shows that they're not just going to be re-creations, but new versions that improve upon the basics.