Half Life 2 Headcrab Hand Puppet


Active Member
Heya RPF, been a while! I've become quite active on the 405th sister site and haven't been around here much lately.

Anyway, time for the real meat of the thread. Over the last year or so, I've been getting quite involved in puppetry and mechanics - I did a Little Shop of Horrors production, a full scale Halo: Combat Evolved Grunt puppet, and recently finished up an Enchanted Tiki Room drummer - my first animatronic. I want to keep expanding my mechanical skills to help bring my creature creations to life. So my current (well, one of many) project: a headcrab hand puppet from Half Life 2.

Earlier this year I sculpted the headcrab in ZBrush, as I attempted to learn the program to get some experience in a widely industry recognised project (as you will soon see, my forte is actually Blender, including the render below).


I will be using this model (and modifying it) to form the skin of the puppet.

The headcrab model was hollowed out, with room for my fingers in the limbs and two rings near the, um, mouth for my middle and ring fingers to hold on to.

What's great is, it's actually very easy to get the basics of puppeteering a headcrab with just your hands! Form a fist, then take the pinkie and pointer finger of both hands and stick them out (rock music makes this step easier). Stack one hand on top of and slightly in front of the other, and that's basically how a headcrab walks (though, the backlegs are dog-legged, as seen in the in game animations).

Recently, I started testing printing with flexible PLA to see if it could act as a replacement to having to mold and cast a latex/silicone skin. I chose flexible PLA over TPU as it's - somewhat - cheaper, easier to print, and can handle paints/sealants better. With my Bambu printer, it wasn't too much of a struggle to print, even managing to retain good detail on walls one perimeter thick (on a 0.4mm nozzle), except for overhangs.


This prototype headcrab was assembled in one whole piece, and coated in Leak Seal. Parts were joined together with glorious Shoe Goo. I digitally sculpted in grooves into the legs to help with bending the joints, like a bendy straw, so they don't splay out so much.

While I was surprised at the flexibility of flexible PLA, it certainly does have its limitations - unlike silicone or latex, it's not able to be compressed or stretched, hence why I had to sculpt those grooves in. It can also be a bit lound as parts snap back into shape, especially when the print is hollow.

But, with these limitations in mind, I am redesigning the headcrab to incorporate more technical capabilities, like articulated joints. That means that the creature will be broken up into sections, instead of being one, intact piece. Sure, it doesn't look as... er, "realistic", but the ability to pupeteer it more easily, and give it more expression, will definitely outweigh that con. Mechanics may be slightly exposed, like Barnaby Dixon's hand puppets, but that's part of the charm that I also adore (I'm the kind of guy who loves hearing the clicking of the animatronics at the Country Bear Jamboree).

As I write this, I've got one final piece printing for an articulated finger I am in a way "reverse engineering" that will allow me to hide some of the mechanisms underneath the finger, rather than on top.

Hoping to get this made in time for Brisbane Supanova in November, and now that I have a full time job... wish me luck!
I've made some strides in the time since the first post. Taking the articulated finger in the last post, I managed to - relatively easily - move the extension mechanism from the top of the finger to the bottom.
Here's a rough diagram of how I planned things to get split:

The model was split so every moving piece is in its own static section. Which... kind of does defeat the purpose of flexible filament, since it doesn't really get to flex all that much. But this would still be a lot harder with solid filament, and the softness of it gives it a more squishy texture, in conjunction with the Leak Seal. The warts feel really weird to touch.

Here's a video of it walking with just the legs:

I haven't got the body segments attached just yet, but my plan is to hold them together with straps of elastic, allowing them to move around and stretch apart if need be.


There's been a number of trials with this headcrab; firstly, for example, the Leak seal doesn't hold all that well and can rub off somewhat easily. After I initially sprayed all the pieces, I decided to strip them of the Leak Seal and sand each piece like I should have done in the first place, to give more adhesion to the sealant. The high friction areas - that is, the claws and back legs - I have covered in Shoe Goo to help protect the sealant wearing off. I will likely go back over them with E600, as apparently that is less chunky.

Another major problem - one which really threw me around - was getting the front legs to work and fit with the mouth segment. They didn't get the range of movement they needed, and because of the angle my fingers were at, I couldn't get the articulation to open and close. So I ended up cutting the sides near the mouth back, to make more room for the legs, and on top of that I realised that if I positioned my fingers in the mouth differently - so that my second knuckles are in the rings, instead of the first - not only did that allow my pointer and pinkie fingers to have much more freedom controlling the legs, it also gives me the ability to move the head segment around, giving more potential for expression.

One slightly minor problem I am still working on is with how the claws roll in, making the headcrab almost look like a gorilla when it walks. I've made the padding quite tight around the fingers, but they still move around too much.
And just like that... the Headcrab is done! I named him Eugene (let's see if you can guess why).

This video was really the first proper test of the puppet; unsurprisingly, tested and filmed the night before its debut convention, Supanova Brisbane 2023.

There's probably not too much to add since the last update. I hand painted the base coat with an acrylic raw sienna paint; the rest was airbrushed on, including shadows and highlights, and to colour the warts (yes, most people who I showed it to, I did ask them to touch the warts as with the coating they are an odd, unsettling texture). I used a few shades of red around the mouth to give it that very gluttonous look.

All individual parts of the body are attached with velcro and elastic, so it's easy to take apart, yet allows the parts to bend around each other.

The skin was then coated in E6000, which as I had been told, goes on much more smoothly than Shoe Goo. I chose E6000 as it is flexible and transparent, but also quite durable to protect against the parts rubbing together.

I may do some future improvements on him. I do definitely need to find some thin, black gloves as my hands being exposed didn't exactly sell it. If I were to remake parts, I'd definitely remake the mouth so that it was easier to move the front legs around.

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