All the way from Dimension X, it's Krang, everyone's favourite evil brain from the 1980s Teenage Mutant Ninja Turtles cartoon!

This instructable describes my experiences transforming a Furby into a latex Krang. This was my first time using liquid latex, and I relied heavily on the advice from n1cod3mus's and PenfoldPlant's instructables.

Step 1: Materials

I used the following materials for this project:

Furby (one of the original ones, not the modern versions) - You can usually find old Furbies at thrift stores for under $5
Plastic cling wrap
2L pop bottles
Masking tape and scrap paper
Plasticine
Liquid latex
Plaster of Paris
Vaseline
Acrylic paint
Fabric medium
High gloss gel top coat
Super glue
Popsicle sticks
Battery clip

Step 2: Dissembling the Furby

To take apart the furby you will need tiny screwdrivers, needle nose pliers and wire snips.

I removed the furby fur and the hard plastic shell that protects the electronic components.

For this project, all I wanted was the moving eyes and ears.

When you take away the circuit board and run power directly to the motor, the furby will cycle through a series of movements, as shown in the video.

After I had removed the unnecessary bits, I cut down the shell and put it back together.

Step 3: Preparing for Sculpting

Before you can begin sculpting, you need to build up the armature, the framework the sculpture will be built on, and protect the furby components from the plasticine.

I covered the furby bits in cling wrap and then built up the shape of Krang's brain with part of a 2L pop bottle, scrap paper and masking tape. I did a layer of papier mache over the head to give it a bit of extra strength to hold up under the plasticine clay.

I used a toilet paper roll as a crude stand.

You'll notice that the furby parts are upside down. The furby ears have become Krang's arm tentacles.

Step 4: Sculpting

Time to break out the modeling clay!

I rolled out thin sheets of plasticine and covered the furby-clingwrap-papiermache monster.

I built up the shape with the clay until I was happy that it looked like my reference photos.

Step 5: Making the Mold

This was my first time making a plaster mold. I recommend that you check out some of the great instructables on how to do this before attempting it yourself.

I used strips of thin cardboard and masking tape to divide Krang into two parts. To hopefully make it easier to remove the mold, I applied some Vaseline. I then mixed up a batch of plaster of paris and spread it on.

After the plaster had set, I opened up the mold to clean it out.

Getting Krang out of the mold was rather challenging. The little plasticine appendages remained trapped in the mold, and while I tried melting them out, in the end I had to spend several frustrating hours fishing out all the little plasticine bits with Q-tips and various skewers.

Step 6: Casting the Latex

I really wish I would have paid more attention to n1cod3mus's and PenfoldPlant's instructables. I didn't really know what I was doing with the liquid latex and I ruined a couple cheap paintbrushes before catching on to the dish soap trick.

I applied several layers of latex to the mold, letting it dry between each layer.

Before removing the latex from the mold I dusted it with baby powder so it wouldn't stick to itself.

Step 7: Soldering

My partner soldered two wires to the motor leads so we could power Krang with a battery pack outside of the puppet.

We used heat shrink tubing to cover the wire ends and electrical tape to hold the wires in place down Krang's back.

Step 8: Fitting the Latex to the Furby

When I first pulled latex Krang out of the mold, I was really excited. Even though the mold wasn't perfect, he looked just like my plasticine model.

I trimmed off the excess latex with an X-acto knife.

Then I went to fit the latex over the Furby guts, and I ran into a problem.

Either the latex was too thick or the design itself was flawed because the animatronics wouldn't work inside the puppet. Naturally, I busted out my dremel to try to sand down the latex in some of the thicker areas that I thought were causing problems, and then I promptly blew a hole through the side of Krang's face.

I cut off his arms because it seemed like a good idea at the time.

I added the bottom of a plastic pop bottle to the top of Krang's head to give him a bit of a skull to support the latex.

Ultimately I used crazy glue and then a little bit of liquid latex to join the two halves of the brain together.

Since the Furby ear bones were not strong enough to support the arm tentacles, I cut them off and replaced them with popsicle sticks.The arms went on with some hot glue.

I wanted to try recasting a much thinner latex puppet to see if that would be more successful but unfortunately I no longer have the mold (you have to make some hard decisions when packing everything you own into a van).

Step 9: Painting

To keep the acrylic paint flexible and prevent it from cracking with the movement of the latex, I mixed in fabric medium before applying the base coat of pink paint.

With a thin paint brush I added the purple and blue vein details.

Finally I applied a glossy gel top coat to give him a slimy look and protect the paint job.