For Halloween I decided to go for something more realistic: a monster arm for any monster costume, which maybe goes along my other "trophies" on the wall afterwards.

If you play too much "Scorn" (the game) and watch too much "Stranger Things" you kinda get stuck with things like this on your mind :-)

So lets start...

Supplies

Construction foam
Modeling clay
Spray primer
Air brush primer
Red spray paint
Kinder surprise yellow halves
Rubber tubes
Cutter
Glue pen
Sanding paper
Air brush
Paint brushes
Paint colors

Step 1: Construction Foam Base

First you have to make a shape of an arm with construction foam. You start doing a lot of forms keeping in mind the form and components you need. In my case a big arm with shoulders and three kreepy fingers. For this you just empty the foam can and do maybe more then you need.

Then you have to cut out the inside of the arm that you can put your arm in. For this a cutter is the best tool since it makes it really easy to form it as you like.

Step 2: Prepare Accessories

I used Kinder boxes, half of them as eyes on the arm. You have to paint them first with primer, or the paint wouldn't stick. After that just glue them on the foam arm.

The rubber tubes are used as cut bones. You can grind the bones with sanding paper giving them scratches and splinters. Priming them is also a safe ideea.

For more bones on the shoulder protection you can take styrofoam and cut it like spiky bones. After cutting you have to grind it to the perfect form using the sanding paper. After that we need 3 more Bones for the claws. The bones also have to be glued to the shoulder and the fingers using the hot glue gun and let it dry.

Step 3: Modelling Clay

For the eye lids, the claw bones connections and the black mold along the arm I used air drying modeling clay.

For the eye lids you have to form some cylinders which need to go around the eyes and the bones. From there you contine making the black mold or black veines along the arm. Those have to look like some infested "Venom"(the movie)-syle entity.

After you are satisfied with the form, let it dry

Step 4: Paint Job

To be sure that every paint sticks, use primer first. It is important to know that spray paint from cans attacks styrofoam (to be sure check on a small rest of the construction foam as well as styrofoam). So use it only on the construction foam and modelling clay. Use air brush primer for the styrofoam bones, or just wood glue.

The next step is to paint everything red with spray paint except the large bones on the shoulder and the claws. Then use the air brush with brown color to paint the dark places. Then you paint with white color the bright spots.

The substance made out of modelling clay has to be painted black with a paint brush.

Then you have only left the bones that are going to be like a dirty yellow white and the eyes you can paint like the pictures using also brushes.