You are correct; this is a very late seasonal greeting, but better late than never, I guess. This poem was first published as "Yuletide Horror" in Weird Tales December 1926, but has since then been included in various anthologies, mostly under its original title "Festival."
The critter at the end of the video is one of my favorite Lovecraftian monsters. It first appeared in Robert Bloch's excellent short story “Notebook Found In a Deserted House”. Here's how it was illustrated by Matt Fox in the May issue of Weird Tales 1951. As you can see it's depicted as a quite traditional devilish creature, but with lots of limbs and mouths, as described in the tale.
It's actually described as a shoggoth in the story, but when gaming company Chaosium included various Lovecraftian monsters in their products they dubbed this creature a Dark Young of Shub-Niggurath instead, and they gave it it's now iconic look of an amorphous body, with stumpy hooved legs. Pretty much as Bloch envisioned it.
Now, I've been wanting to build and animate this monster for a few years and I actually made a set of hooves about four years ago. I sculpted them in Cahavant clay and then cast them in SmoothCast 365 plastic from one silicone mold. The three hooves are hollow, and to attach them to an armature I've drilled holes in the top of each hoof.
Starting off with the legs, they are as usual made from a few strands of aluminum wires, sectioned off with short steel nails held in place with yarn wrappings. This creates small joints between the nails that allows the legs to be animated in any direction. So why not simply have the wires without the nails? These legs will be like small octopus arms anyway. The nails actually helps the legs become sturdier, and the joints between them less bouncy and jiggly. In other words, the animation will be easier to perform. The finished leg armature goes into the top of the hoof and I'm using melted polymorph plastic to fix the armature to the inside of the hoof.
It's time to add the actual tie-down function to their undersides of the hooves. I'm filling up each hoof with a fast-setting plastic called Rhino, and before the material cures I'm adding a t-nut with a screwed-in bolt to create the tie down. The t-nut has a longer threaded canal than the wing nuts I usually use, and will therefore take a greater weight and add more stability to a puppet during the animation. Since this puppet will be larger than what I usually build, this was a sound solution. I simply hold the t-nut in place while the plastic sets. I need a screwdriver to get the rod unstuck from the plastic, but when I use it during animation to clamp down the puppet on the animation stage I can add and remove the rod with my fingertips.
These aluminum wires will become the crown of tentacles on top of the dark young. I've ground down the rather thick wires in one end so they become very slim and pointed there, and the other end is twisted into a loop for attaching to the leg armature part.
I'm covering all of the tentacle armatures with a wrapping of thick yarn. No nails or other reinforcements are added, as the tentacles won't be carrying any other weight than their own. The yarn is soaked in a couple of layers of tinted latex. And I'm using my heat gun at a low setting to speed up the drying process.
This potato-like blob is a chunk of medium grade monster clay, into which I've stuck the finished tentacles. I could've built up the body of the puppet using cotton and polyurethane padding, covered with patches of latex skin, but I decided to sculpt it instead, which allowed me to add more organic details that seemed to flow into and out of each other. I'm mostly using loop tools to create the wrinkly and warty shapes on the skin.
Here's the finished sculpture, ready to have a plaster mold created around it. Half-pearls or sequins, if you will, are added as eyes into the sculpture. As I'm sure you know by now I use these scrapbooking items as cheap eyes on many of my puppets. They're very effective as they reflect light aimed at them, and appear to be glowing. To smooth out details I use stiff oil painting brush dipped in Vaseline.
The first layer of plaster is carefully brushed on. I go over the surface of the sculpture many times to ensure there are no air pockets. You can see that I've added a short wall of clay around the base. This is so the plaster won't run out all over the turntable.
After this first layer I'm building up that clay wall to completely cover the height of the sculpture. This allows me to simply pour in the rest of the plaster and let it rise to fill this clay shell. I could've added several layers of plastic one at a time, but this is much faster.
I'm casting the body of the puppet as a skin made from tinted latex. I'm pouring in a small batch and painting the latex into all areas using a q-tip. I'm adding four layers of latex, allowing each layer to dry properly before adding the next. When the latex has cured I powder it with talcum and pry it loose from the mold.
I cut holes in the latex where the tentacles will be attached and where the eyes will be put in. I'm actually using a bit of very strong chroma key gaffer tape to stick the eyes to the inside of the latex skin. The tape will flex with the skin and still keep the eyes in place.
I have sculpted a bunch of open mouths into the body. To be able to animate those I'll have to add some aluminum wires to the inside of the rims of the mouths. I do that by wrapping some aluminum wires with soft string, helping it stick with a dab of contact cement. When the string wrapping is complete I cover it with latex, and the wire can now be turned into a loop. As you can see I've left the ends uncovered. This is so I can join them together using super glue and baking soda, which when mixed will turn into an incredibly hard and durable material. I add some more string and latex to this uncovered bit, and we have a mouth armature which can be animated folding and opening in any funny direction. Each mouth armature is glued to the inside of the latex skin using liquid latex as a bonding agent.
The latex-covered yarn on the tentacles does add some texture, but I want something the looks softer and a bit more sculpted, so I'm casting some latex into old skin mold with a very wrinkly look. When these patches of latex have dried I peel them off the mold, dab them with liquid latex and wrap them around the tentacles. I'm also adding some drops of latex to create warts and bumps on the skin.
With all tentacles finished it's time to add them to the body. I cover the area where the tentacles go into the body skin with latex and bits of cotton, and use the heat gun to make the latex cure faster. This will fix the tentacles to the body skin. When that's done I add melted Polymorph plastic to the inside. This will fix the tentacles to both the latex skin and to each other. The teeth are small bits of latex simply rolled between my fingers until they harden as tiny pointy bits. These teeth are glued in place using liquid latex which permanently makes them a part of the body skin.
The legs get wrapped with thin polyurethane foam until I get the desired look and thickness. The seam between plastic hoof and foam is covered with cotton soaked in latex. I'm using more contact cement to make sure the cotton stays in place. Like the tentacles, the legs are covered with patches of latex skin cast in a wrinkly skin mold.
To pad out the bottom of the puppet I'm cutting out a couple of bits of camping seat cushion, and gluing them together using contact cement.
I wanted the underside to be warty and weird-looking, so I turned to my little cookie box of surplus castings I've made over the years. If you keep latex castings dark and pretty airtight they will last for quite a while. So every time I've made castings but not used all of them they go into this little box. These patches of warty skin are stuck in place using latex. Since the seat foam on the underside is slightly porous it'll accept the latex and bond with it.
The puppet gets a thin covering of tinted latex to help unify the various added bits. Then I go over it all with an airbrush and acrylic paint with highlights and added colors.
It would've been great fun to actually adapt "Notebook Found In a Deserted House", but that story is copyrighted, and the estate of Robert Bloch is probably not to be trifled with. Nor is Chaosium, but I think my use of this monster is within the "fair use" appreciation.