Ever wanted a real life Thwomp? They are great at keeping intruders away from your house! : )

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Step 1: Designing the Mold

Supplies Needed:

  • Computer
  • Printer
  • Scissors/X-acto Knife
  • Spray Glue


  • Paper
  • Poster Board
  • Cardboard
  • Tape

I started out by finding a picture of Thwomp that I could use to create a template, a quick online search and I found the perfect one.

Once I had a good picture, I decided on a size and the final measurements came out to be 15 5/8" tall x 14" wide x 7 1/2" deep.

I printed out a picture of Thwomp in my desired size and began making a cardboard mock up of the mold. I knew I wanted to make the mold box out of wood but it was easier for me to do a mock up first so I could figure out all the pieces I needed to create.

I designed the mold as a box, and created pieces to fit inside so that once concrete was poured in they would create the Thwomp face and spikes. I created pillars which I positioned around the sides of the box to create the spikes on the edges. I created a border for around the face so that the face would end up sticking out about 1". Then I created the pieces for the facial features, this took me a minute to figure out because I kept getting confused on what needing to stick out and what needed to be indented in the concrete : ) but I ended up realizing that any piece I created to go in the mold box would end up being indented simple now!

After I created the cardboard mock up and figured out all of the pieces I needed I designed a clean template in illustrator. I altered the shapes of the spikes so I could cut the pillars using exact degrees and finalized the design.

Once the template was complete I printed it out and taped it together. I have also included the template I used so you can create the same thing! : )

Then I used spray glue to attach the template to some poster board so that it would be nice and thick, I really don't like flimsy pattern pieces... : ) but that's completely optional.

Then I cut out all of the pieces and was ready to get going to the wood form!


*I included my process in making the cardboard mock up but you would not need to do this to make this project, I just added it in case anyone might find it helpful for their own projects : )

* I ended up modifying the corners of the Thwomp to square them off to make the mold box a little simpler and easier to work with, the template is updated with the squared corners.

Step 2: Cutting Out The Facial Features And Spikes

Supplies Needed:

  • Jig Saw
  • Bandsaw
  • Router
  • Router Bits (large and small, I used a 3/4" and a 1/8" straight bit)
  • Clamps
  • Safety Glasses
  • Shop-Vac
  • Pen
  • X-acto Knife/Scissors
  • Cutting Mat


To create the facial features and spikes I started by transferring my template to the particle and MDF board.

I used 1/4" MDF board for the eyebrows, I didn't want them to be as deep as the rest of the facial features.

Once I traced the eyebrows to the MDF board I used a jig saw to roughly cut out the shape so it would be easier to cut in the bandsaw. Then I used the bandsaw to cut out the eyebrows, keeping the blade on the outer edge of the pen mark and cutting very carefully around the curves.

Next I traced the mouth, eyes and spikes on the 1/2" particle board.

Once traced I roughly cut these pieces out with the jig saw.

Then I cut out each piece using the bandsaw. I liked using the bandsaw to cut out the pieces because it was easier for me to maneuver the pieces around. This was actually easier than I thought to cut out the curves, I just took my time and tried to stay on the lines. * If you are lucky enough to have or have access to a laser cutter that would come in very handy here!...P.S slightly jealous! : ) ...okay...very!*

The last step was to add the teeth detail to the mouth. I cut the teeth out of the mouth pattern piece and transferred the pattern to the mouth piece. Next I clamped the mouth piece to my table and I also clamped a shop-vac right next to where I was working to catch some of the wood shavings. *The router was super messy to work with so I would definitely recommend using safety glasses and a dust mask*. I used a 3/4" straight bit for the first round to router out as much of the teeth as possible, and I set the depth to about 5/16". Then I used a 1/8" straight bit to define the corners and square them off.


*I used a 1/8" blade on the bandsaw which made it a lot easier to cut out the curves.

Step 3: Creating the Face Frame

Supplies Needed:

  • Table Saw
  • Bandsaw
  • Jig Saw
  • Drill
  • Drill Bits ( I used a small bit for pre-drilling the screws, a phillips head, and a large bit for cutting out the center of the face frame)
  • Grinder
  • Caulking Gun
  • Hot Glue Gun
  • Clamps
  • Speed Square
  • Pen
  • Paint Stirrer ( or anything to use as a spatula to spread around the wood glue)


To create the face frame I started by cutting out 2 rectangle pieces the size of the Thwomp, which measured 14" X 15 5/8", from the 1/2" particle board using a table saw.

Next I glued the 2 pieces together. I started by tracing the face frame to one board so I would know where I needed to apply the glue. I applied a bead of the Liquid Nails Glue to the board and spread out the glue using a paint stirrer. Then I added the 2nd board, making sure to line up the edges and pressed them together.

Then I added some screws to make sure the boards would be secure. I clamped the boards to a table and added screws to the spikes. I pre-drilled all of the holes since the particle board can crumble fairly easily.

Since the screws were a bit to long, I used a grinder to grind them down and smooth out the back side.

The next step was to cut out the center of the face frame. I began by tracing the face frame template to one side of the board. I clamped the face frame to a table and used a jig saw to cut out the center. I drilled holes in the corners since these are pretty tight curves, this made it easier to cut with the jig saw. * I was so excited when I was done! I was really worried about staying on the lines, but I took my time and it came out clean : ) *

Next I cut out the spikes. I used the bandsaw to cut them out and this was a lot easier for me to use instead of the jig saw in order to create straight lines.

The last step was to glue on the small spikes to the face frame. Adding these will create a little wall around each spike so it looks like the real thing. You just want to add the small spikes to the correct spike on the face frame. I added hot glue to the back sides of the small spikes and pressed them into place.


*I wanted the face frame to be 1" thick so that the face would stick out 1". You can always adjust this size as desired. I used 2 pieces of wood glued together because it was more cost effective but you could also use a piece of 1" thick board and skip the gluing process.

* I originally cut the corner tips of the face frame in order to get the Thwomp to look as accurate as possible, but didn't find a good option when trying to add this to the mold box and ended up squaring them off in the mold box.

Step 4: Creating The Mold Box

Supplies Needed:

  • Chop Saw
  • Table Saw
  • Drill
  • Drill Bits (I used a small bit for pre-drilling the screws, and a phillips head)
  • Glue Gun
  • Clamps
  • Speed Square
  • Pen


To build the mold box I started out by cutting the pillars (to create the spikes) out of a piece of 2X8 using a chop saw. The chop saw was adjusted to the correct angle for each piece. The cuts needed are: 4-25X25, 4-25X40, 4-25X45, and 4-30X30.

The next step is to cut out the pieces to create the actual box. I cut these out of a piece of 3/4" particle board, and the cuts needed are: 1-14"X15 5/8", 2-14"X8 1/4", and 2-17 1/8"X8 1/4". Once the boards are cut, you can screw them together. I started by clamping the base to a table and screwing on 1 side at a time. I pre-drilled all of the holes to keep the particle board from crumbling apart.

Once the box is screwed together you can add the face frame to the bottom. The face frame should be positioned with the small spike layer facing up. I added hot glue to the back side of the frame and pressed it into place on the bottom of the box.

Next I added the pillars in between the spikes. I matched each pillar to the correct position (you can reference the pattern for this) and used a speed square to keep them straight. I screwed the pillars to the mold box and pre-drilled all of the holes.

The last step was to give the box a quick sanding to make sure it was as smooth as possible.


* I had my pillars cut and ready to go for a few days and they got warped from the heat so I soaked them in water to straighten them back out. This worked great and I was still able to use them.

*You want to make sure to check if the pillars will lay flush against the edge of the face frame before gluing the frame to the bottom so you can see if everything will fit properly.

Step 5: Attaching The Face

Supplies Needed:

  • Hot Glue Gun
  • Speed Square
  • Tape Measure
  • Pencil


  • Mold Box
  • 1 - Eyebrow Piece
  • 2 - Eye Pieces
  • 1 - Mouth Piece

To attach the face I started by calculating where each piece needed to be positioned on the bottom of the mold box.

I began by drawing a line down the center so I knew where to position each piece.

I started with the eyebrows. I measured from the center of the eyebrows and marked there position at 3 7/8" down from the top. Next I added hot glue and pressed them into place.

Next I added the eye pieces. I measured from the top of the eyes and marked there position at 2 3/4" down from the top. Then added hot glue and pressed them into place.

The last piece was the mouth. I measured from the bottom center and marked the position at 2 3/16" up from the bottom. Then added hot glue and pressed them into place.

Step 6: Preparing The Mold Box

Supplies Needed:

  • Caulking Gun
  • Wire Snips
  • Small Brush


To prepare the mold box I started by adding caulking to all of the corners and cracks. I applied a small bead strip of caulking at a time, wet my finger in water and then smoothed it out. The water kept the caulking from getting tacky and made it easy to manage. I also used a small brush to get into the tiny cracks. I kept a rag nearby to keep my fingers clean and wipe off any extra caulking.

Next I created a wire frame to insert into the mold to help retain the structure. I used concrete tie wire to create a grid frame.

Once the caulking was dry I added a sealer to complete the mold. I used clear spray shellac and sprayed the entire inside, and let it dry completely.

Step 7: Pouring The Concrete

Supplies Needed:

  • Drill
  • Paint Mixer
  • Palm Sander
  • 5 gallon bucket
  • Trowel ( I used a few different sizes for the larger and narrower spaces of the mold box)


Now the exciting part...pouring the concrete! I started out by spraying on a layer of coconut oil to use as a mold release. I have seen a lot of different options to use as a mold release but I had this on hand so that's what I used.

The next step was to mix the concrete. The mold box needed about 1 and 1/3 of 60lb bags of concrete to fill it, so you could probably also just use 1 80lb bag. I added 1 bag of concrete at a time to the 5 gallon bucket and then added water. The mix needed around 3/4 of a gallon of water per 60lb bag, but this will depend on the concrete mix you use. I mixed the concrete using a drill and a paint mixer until everything was thoroughly combined.

Next I added a layer of the concrete mix to the mold box. I filled in a few inches and then added the wire frame, being careful not to press the frame down so it wouldn't sink to the bottom and show on the face. I shook the box a little to settle the concrete and then began filling in the rest of the mold box.

Once I got to the top I used a few different sized trowels to smooth out the surface. I also used a palm sander, without the sand paper, on the outside of the mold box to vibrate out any air bubbles.

When I had the box completely filled and leveled off, I added a wet towel to the top to help retain the moisture while the concrete cured. * I poured my concrete on a particularly hot day so I checked it every few hours and moistened the top with some water to prevent it from cracking.*


* The 5 gallon bucket I used ended up busting open during the final mix, so if you are using a bucket as well just be careful not to press to hard while mixing.

Step 8: De-Molding

Supplies Needed:

  • Chisel (I used a few different sizes)
  • Awl
  • Shop-Vac


  • Mold Box

Now another exciting part! De-molding : )

I had originally intended to preserve my mold box so I could get some more use out of it, but ended up having to take it completely apart. I had poured my concrete on a hot day and it started to show some cracks on the back side so I added a few doses of water to moisten it back up. While this definitely helped the concrete, it soaked my wood frame and and when I started de-molding the wood began to crumble apart.

I started the de-molding process by unscrewing all of the screws around the box, then taking off all of the walls and pillars.

Next I removed the face frame. The hot glue on the small spikes and the face did not hold, so these pieces were still stuck in the concrete. I used an awl and a few different sized chisels to remove all of the small spikes and the facial features. This part was pretty tedious but luckily I was waaaaaaaaaay to excited to reveal the Thwomp to worry about it! I had a shop-vac on hand to vacuum up the bits of particle board as I went along.


* These are the steps I took for my mold box but if you secure the facial features and small spikes with something stronger than hold glue, and allow a longer curing time, than the de-molding process should be a lot easier.

Step 9: Cleaning The Surface

Picture of Cleaning The Surface

Supplies Needed:

  • Chisel


  • Sand Paper
  • Concrete Thwomp

After de-molding the Thwomp, there were a few areas that needed to be cleaned up and sanded down. I used a chisel on the corners that had a little excess concrete sticking out. Then used some sand paper to smooth out any rough areas on the surface.

Step 10: Paint The Face

Supplies Needed:

  • Paint Brushes ( I used a medium and small size)
  • Plate ( Or anything to mix your colors on)
  • Cup


  • Red Paint (I used Americana Multi-Surface Satin in Lipstick)
  • Black Paint (I used Americana Multi-Surface Satin in Black Tie)
  • White Paint (I used Americana Multi-Surface Satin in Cottonball)
  • Paper Towel
  • Water

The most exciting part! Painting the facial features!

I used a medium size brush for the larger areas and a small brush to get into the tiny cracks.

I painted the face on my Thwomp so that he would look like the real thing.

I started by adding the black to the mouth and the eyes.

Next I added the white to the teeth and the eyeballs. The white needed a few coats to really pop.

Then I added the red eyes. (starting to com alive!)

Lastly I finished with the black pupils.


For the paints, I used what I had on hand. The bottles say they are for multi-surface and work for indoor/outdoor.

Step 11: Enjoy!

Picture of Enjoy!

The very last step...Enjoy! Now you have a real life Thwomp! Put him on your front porch and throw out your beware of dog need for those anymore...if you have a Thwomp at your house, people will no you mean business ; )

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msquaredgt6 months ago

This is awesome on so many levels!

mactothefuture (author)  msquaredgt6 months ago

Haha Thanks! So glad you liked it! : )

kwelsh7206 months ago
i used 1/2 inch plywood rather than particle board and had few issuess with water absorbance and demolding.

Also, as a tip, I flattened the sharp end of a screw and drilled it into each of the facial features. This pushes the screw into the hard cement, because the screw is flat, it has a hard time penetrating the cement and instead, the wooden feature rides up the screw as it spins! it worked excellently! Occasionally, the peice did not come out straight and by putting pressure on the higher side and there by squaring it out, it slid out just fine!
I did have two chunks fall out on the corners :/ but I plan to get Thin Set Cement and sharpen all the cracks and chunks that fell out:)

Thank you for this perfect and detailed instructable! I love how my Thwomp is coming out<3
mactothefuture (author)  kwelsh7206 months ago

That is soooooooooooooooo Awesome!!!!!! Great idea with the screws! I'm sure that came in very handy!! (slightly!) haha! So happy to hear that you love your Thwomp!!!! ( me too!!) Thanks for checking out the project and letting me know how it worked out for you!! : )

branden0502 made it!6 months ago

it's not quite as good as yours but here's mine.

mactothefuture (author)  branden05026 months ago

That looks AWESOME!!! So cool to see another one!! How was the build? Did you have better luck with the face? He turned out GREAT!! Thanks for sharing!! : )

i had to use a scroll saw instead of a band saw, and that was a little difficult, but still worked. When I was digging the wood out of the spikes i broke the ends off of 3 of them, if you look close enough you can see where i fixed them. I used a scribe to get the rest of the spikes out and it worked much better, It took a LOT longer, but it meant no more broken pieces. Now what I want to do is mabye put some anchors in the side and hang it from my porch above the steps......

mactothefuture (author)  branden05026 months ago

I'm so glad everything worked out for you! I haven't used a scroll saw before, I'm guessing the size difference made it more difficult? It took me a LONG time as well to dig out the face! Lol but well worth it! I also forgot to put on gloves and had quite a few war wounds on my hands from trying to carefully remove those spikes! I don't see where the ends broke off so nice job on fixing them up! And I must say if you do hang yours up you will definitely a Real Life Thwomp! haha! (make sure its secure! lol) ; )

goldlego7 months ago

I admire all the work you put into that, especially with the details. It came out great!

mactothefuture (author)  goldlego7 months ago

Thanks so much!! Glad you enjoyed the project! : )

MrBeta7 months ago
Great project. Showed my wife and now we're planning to make several for our garden.
I'll try to use melamine shelving to preserve the molds.
mactothefuture (author)  MrBeta7 months ago

Thanks!! That is going to look so awesome!! I'd love to see an action shot when you guys finish! : )

poofrabbit7 months ago

Congratulations on being a finalist in the Concrete and
casting contest! Best of luck to you!

mactothefuture (author)  poofrabbit7 months ago

Thanks so much!!!! : )

thecapper7 months ago

Wonderful 'ible. Seriously good-looking Thwomp!

branden05027 months ago

is there any particular reason you can't use regular plywood to make the mold. It's cheaper than particle board.

Depends on what part of the mold. Particle board has a smoother surface. If the concrete is in contact with it it will pick up the texture.

Although plywood is more moisture resistant and durable. Choose one with an X in the description (at least in the US). CDX plywood is made with exterior rated glue so would hold together better.

Shelving can make nice molds also. But it will probably cost more than a sheet of particle board or plywood. But it would be easier to get home if you have a smaller car.

You could also line the plywood with something smooth. Flexible cutting boards are low cost, reusable and easy to trim down.

Makes sense. Thanks for the input. I'm sure the few extra dollars for the particle board will be worth it in the long run. I hope to make this next weekend. I'll update when I get it done
mactothefuture (author)  branden05027 months ago

Can't wait to see it! Glad you got the info you needed, this is why I love instructables! (Thanks for that pumpkinseed456!)

jlytle-17 months ago

Fantastic garden guardian! This would look epic next to some crushed garden gnomes.

mactothefuture (author)  jlytle-17 months ago

Haha Thanks!! Yes! That would awesome! : )

dgarnier7 months ago

Thanks for the quick reapply, you got my vote, i will give it a try myself in the near future! wow it looks so good!

mactothefuture (author)  dgarnier7 months ago

Thanks for the support! I hope you try it out, it was a fun project! : )

Ayce7 months ago

I've been looking for a new wood project to start... maybe this will be it. Very cool idea, and thanks for sharing.

mactothefuture (author)  Ayce7 months ago

Cool! It was funt to watch it come to life! Thanks for checking it out! : )

Eh Lie Us!7 months ago

Fantastic work. You attention to detail is impressive.

mactothefuture (author)  Eh Lie Us!7 months ago

Thanks so much!! Appreciate the kind words!! : )

cvanderveer7 months ago
definitely on my to build list now! great instructable! :)
mactothefuture (author)  cvanderveer7 months ago

Awesome!! Glad you enjoyed the project! : )

Bartoche7 months ago

I spent 30 minutes in my office reading your instructable and planning to do one! Vraiment génial!

mactothefuture (author)  Bartoche7 months ago

Awesome! Glad you liked it! Hope you do it!! Merci mille fois! : )

patsheldon7 months ago

holey crappers! NICE!

mactothefuture (author)  patsheldon7 months ago

Haha! Thanks! : )

carsam7 months ago
this is completely AWESOME! I have to try to do one like this one, probably not that thick but half thick but congrats it's really fantastic!
mactothefuture (author)  carsam7 months ago

Thanks so much!! I hope you do! I would love to see it! : )

Wolf bro 1097 months ago
dude this is awesome!!!!!!!!you have my vote!!! It's so creative! Can you try to make a piranha plant out of silicone so that it can chomp and move around like in the game? please?!
mactothefuture (author)  Wolf bro 1097 months ago

Thanks so much!!!! I have to say your comment put a smile on my face! What a specific request, lol! Sounds like I cool project! Hopefully I can tackle that someday! : )

akshat210457 months ago

Wow! You totally got my vote! 100 lbs of pure awesomeness!

mactothefuture (author)  akshat210457 months ago

Yes totally worth the weight!! Glad you liked it and thanks for the support!!

Looks so cool!
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