Silicone/Oogoo Brain Slug From Futurama (Updated)




Introduction: Silicone/Oogoo Brain Slug From Futurama (Updated)

This halloween i decided to make a Brain Slug from Futurama, a totally awesome science fiction cartoon. I received enough compliments on it that I decided to share how I made it. I had seen many crocheted and fabric brain slugs online but as I have no experience with sewing or crocheting and because I wanted it to be kind of squishy, i made it out of silicone, or more specifically, oogoo. Oogoo is a clever mix of corn starch and silicone caulking that was first described in this insanely handy instructable. Brain slugs are cute little parasitic creatures that, depending on the episode, are either semi-transparent green or that glow-in-the-dark pale lime green color. I went with the second one as oogoo isn’t transparent, though I did make it glow, as glowy stuff makes everything better.

Update: I decided to update my brain slug to improve some aspects I thought were lacking in the last one and also to make it even more glowy. Step 8 has the update

Step 1: Supplies and Tools

For the basic oogoo you will need:
Silicone caulk, get the stuff that has a warning about acetic acid vapors(the vinegar smell that it gives off)
Corn starch
Green food coloring

For the mold you will need:
a small yogurt container
a ball of similar diameter to the top of the yogurt container
hot glue
duct tape
rubbing alcohol(optional but greatly helps release the hot glue, learned about it from this instructable
wax paper

For the eye you will need:
white plastic (got mine from a milk container)or thick paper
a washer, or something circular to trace.
A small nail
a black marker.

For the glowy bits:
led keychains
a bit of cardboard/foamboard
green diffuser (I used a green tailswitch from a flashlight)

Other various tools and stuff you will need:
hot glue gun
caulking gun
something to mix the oogoo in, I used a plastic tub
something to mix with, I used a plasic knife and a paint stirring stick
a hat you are ok with cutting up

Step 2: The Mold

The mold takes advantage of oogoo's handy trait of not sticking to some plastics, hot glue or duct tape. For the main vertical part of the body I simply cut off the top and bottom lips of the yogurt container so that I was left with a smooth conical cylinder. The dome part was made by covering half a ball in hot glue. Next I pealed back this layer till I was left with a little half spherical shell of hot glue. Dabbing rubbing alcohol around the edge of the shell really helped here to release the hot glue bonds to the ball. Using the hot glue gun tip I melted holes for the antennae to stick through. I then hot glued the dome and body together. The foot/base part is just some cardboard with a hole in it hot glued to the bottom of the yogurt container. On top of that I put duct tape and used hot glue to make a thin wall in the shape of the foot. The antennae themselves were molded by just smearing some oogoo on wax paper and then rolling the wax paper into a tube shape.

Step 3: The Oogoo

I used a 1:4 cornstarch to silicone mixture (by volume) to make the oogoo nice and translucent. Food coloring goes a long way and I figured out how much to use by experimenting when I was first making the antennae. For the main body I combined the starch and silicone together and then added just 2 drops of green food coloring. Having made the antennae first also allowed me to simply bend the antenna tube in a “U” shape and insert it through the holes in the dome to secure it in place. Next I transferred my mixed up green oogoo to the mold using a large paint mixing stick and then pushed it against the walls using a plastic knife. The walls ended up being about 5 mm or 3/16th an inch thick.

Step 4: The Eye

I made the eye by tracing the outside and inside diameters of a washer onto white plastic. I cut around the outside of the washer to make the general circle, then filled in the inside diameter with marker to make the pupil. To secure it, I bent a small nail into an “L” shape and pushed it through both the eye and the body of the brain slug. I finished up by coloring in the nail head so it blended in with the pupil.

Step 5: Making It Wearable

I had thought to use bobby pins or even an elastic band to attach the brain slug to my head but I felt that it was a bit too heavy for either of those. I wanted a method that was easy to take on and off, wasn't too firmly attached to my head(in case someone grabbed it) and was quite secure. A hat with a hole cut in it ended up meeting all those requirements. While I had initially wanted the foot of the brain slug to be visible, it ended up being very useful in securing the brain slug in the hat while allowing the body of it to poke through the hole.

Step 6: Making It Glow

Ok, so the brain slug doesn't glow in the show, but I wanted my brain slug to glow. We can pretend that either it or my brain is bioluminescent, or maybe both. I was running short on time here so I glued 2 cheap led keychains to a circlular foamboard base and put a green diffuser on top of it. The circular base fit snuggly in the bottom of the brainslug and illuminated it quite nicely.

Step 7: Potential Improvements/Lessons Learned

I did this in a bit of a hurry as I waited to the last minute to make it. One thing I learned is to make this a couple days before hand to let the vinegar smell completely dissipate. I made it the night before halloween and so it was still a bit strong smelling by the time I had to wear it. Another thing I learned is to use fresh or at least semi-fresh silicone caulk. I had made another brain slug several days beforehand with some old caulk I had laying around. Even though it was the right type of silicone caulk, it must have been semihardened or something as it was terrible to work with and took forever to set. I might also change how I attached the eye. The nail works, but I am not overly fond of having a small nail on top of my head. I would think a proper glue would work, or maybe just something plastic instead of the nail. Lastly, I wonder if a wig would look more natural than the hat.

Anyways, I enjoyed wearing the brain slug and was happy to see people recognize it. If you decide to make a brain slug for yourself, please feel free to share. Its always good to spread the Futurama love.

Step 8: Update: More Glowy Bits

I decided to make the antennae and eye glow while illuminating the body with a slow led chaser(which a commenter and several friends had suggested).  I used the same mold for the body but I cast the eye and pupil out of oogoo as well.  The mold for the the eye was just a disposable measuring cup that comes on medicine bottles(like pepto bismol or whatnot), while the pupil was cast inside a washer.   The oogoo mix for the eye was left uncolored, leaving it a nice white.  I wanted the pupil to be extra dark and have no light leak through it so I added black, as well as blue and red to the mix(i found the black to be a bit green to me).  Oogoo sticks to itself really well so I used a thin smearing of it to attach the pupil to the eye and the eye to the body.  I made the antennae in a similar fashion to before(rolling it up into a tube of  wax paper) but then inserted awls to give it a hollow conical section that would distribute the light better than just solid oogoo. I cut holes in the top of the mold for the antennae(i had taped over the holes in the mold previously) and  glued the antennae in place so that  I could put  leds into the internally exposed hollow end of the antennae.   The eye and the antennae were illuminated with a very simple circuit of  3 leds (2 green and 1 white )in series that was run off a 9 volt battery.  

The body  was illuminated with an awesome led chaser kit from the instructable user ledartist.  I chose this kit because it had soo many different functions to choose and speed variations for all of them.  The only modification to the kit was that I ran wires out to a battery holder, instead of using the on board battery holder clips.  Those clips were what I used to mount  it to a foamboard  holder that kept the led chaser in the center of the brain slug.  I wrapped the chaser in a layer of wax paper to help diffuse the leds a little.   The power lines to both batteries were run out the bottom of the brainslug and taped into place on the inside of the hat. 

I am quite pleased with this update. I really like that the eye is a little more proportionately sized and that it glows white, which I think makes it visually pop a bit more.  I think the slow upward led chaser provided from the kit really improves it without being a flashy eyesore.  Anyways,  I enjoyed making this updated version and hope others enjoy it as well.

Make It Glow Challenge

Participated in the
Make It Glow Challenge

Be the First to Share


    • Home and Garden Contest

      Home and Garden Contest
    • Tinkercad to Fusion 360 Challenge

      Tinkercad to Fusion 360 Challenge
    • Electronics Contest

      Electronics Contest


    This looks so cool. I want one.

    I think it would look better with a wig, as you said. Also, I would probably try making the eye with Oogoo, and then attaching it with a little blob of Oogoo. But, I haven't actually made anything using Oogoo yet, so I don't know that it would work.


    It's not the best looking brain slug I've seen, but the glow really makes this a cool project. I would add a few more LEDs and light them with a slow chase effect so that it looks like the brain slug is sucking something up from the host's head.


    Reply 8 years ago on Introduction

    Several people had similar suggestions so i went ahead and updated it this year. the slow chaser really makes it. thanks for the constructive ideas.


    9 years ago on Introduction

    This looks really cool, except for the eyeball. It's curving the wrong way. You could improve the look if the eye conformed to the curvature of the slug's body. Could you have used glue instead of the nail?


    10 years ago on Introduction

    thanks for the warm words people. :)


    10 years ago on Introduction

    "And what are the Brain-Slugs who control you going to do for us?"...


    Awesome! I love that you added it to a hat AND made it glow! Really makes a difference.