Bowser Costume, Part 2 – The Shell October 17, 2013

DIY Bowser Shell for Costume

Did you miss part one of the Bowser costume series?

In part two, we’ll cover just the shell. This is a really flexible project and could easily be adapted as a pillow or turtle shell if that’s what you’re looking for. For a pillow, I’d advise against using the felt and instead stick with fleece or something more durable. I know I’d be making a million of these little Bowser shell pillows if there wasn’t so much hand sewing involved! The materials required for this project are discussed in part one.

A note before we begin – I was making this up as I went along, and did some things that perhaps weren’t necessary. Do as I say, not as I do!

First, you’ll need a large piece of cardboard. This will help with the structural integrity, as well as limit the amount of stuffing you need. If you’re making a pillow, you can skip this step! Determine the size of the shell (for a costume) by measuring the distance between the neck of the jumpsuit and the top of the tail. Sketch an oval roughly that size on the cardboard. You don’t need to be a perfectionist about it – this will all be hidden under quite a lot of material and stuffing. Cut out the oval and make four cuts, shown in the picture as red lines, where the corners would be if it were a rectangle. This will help us shape the shell.

Cut out the oval, and make cuts along the red lines.

Cut out the oval, and make cuts along the red lines.

Overlap the cut edges to pop the center of the oval up a bit and tape them together, as in the photo below. Place your oval on a doubled layer of green fleece and cut about two inches outside the oval. (The photo shows more than two inches, but the extra wasn’t necessary.)


Cut a piece of iron-on batting just slightly larger than the cardboard. Adhere this to the wrong side of the fleece that will be the top of the shell.

Now let’s work on the spikes. If you’re making a turtle shell, you can skip this step, unless it’s a particularly bad-ass turtle. Cut ten half-circles out of felt. The necessary size will vary based on the size of your shell, so try making them out of paper and setting them on your shell until it looks right. Remember that your felt spike will be a bit smaller after sewing and turning it, so make it just a little larger than necessary. Bowser has four spikes down the center and three spikes on each side of his shell. Fold each half-circle in half, corners together, and sew along the straight edge. Clip the point and turn the spike inside out.

My half-circles were about 4.5" in diameter.

My half-circles were about 4.5″ in diameter.


Lay the green fleece with the batting on top of your cardboard oval, right side up. Place your spikes in their desired positions, if you’re using them. With white chalk, draw hexagons on the fleece – around the spikes or however you like. Remove the spikes and machine sew along these lines and through the batting.

hex quilt

When I did the next part, I sandwiched the two layers of green fleece, right sides together, and sewed around the edges. Then I turned it inside out. What I would do differently is stuff the spikes, pin them in place (bottom edges turned under slightly, seams facing the bottom of the shell), and hand sew them on. Then I would have basted the two layers together, WRONG sides together, with the cardboard and stuffing in place. There is really no reason to turn the shell inside out since the raw edge will be encased anyway, and it would have been a lot easier to sew the spikes on with access to the back, not to mention sewing through half as many layers for the edge. If you choose to do it the hard way for some reason, be sure to leave a gap large enough to insert the cardboard oval and stuffing. Don’t be surprised if your shell looks like a giant misshapen blob at this point – the binding should clean and tighten it up a bit!

pinspikes stuff

For the binding, we’re basically going to make some giant single fold bias tape (though I didn’t cut mine on the bias). Measure the circumference of the shell and add four or five inches. This is the length of felt you should cut. The width will just depend on how fat you want your binding. My tape was about four inches wide, plus an additional 1/2″ on each side. Fold and press the edges toward the center.
If you need a little help sewing bias tape on a curve, here’s a nice video that explains it. It’s worth a watch before trying this, as this is the method I used. First, unfold one edge of the tape and pin it to the top of the shell, right sides together, all along the edge of the shell. Start at the bottom of the shell. When you reach your starting point, trim the excess tape and make sure to fold the end of the tape under a bit, positioning the folded edge under the raw edge so you end up with a nice seam. Sew the length of the tape, staying right on the fold line.

pinedge sewedge

Fold the tape over to the other side and stuff it with polyfill, pinning in place. Stitch it closed along the seam. You may need to do this by hand – I did, but of course I had more layers to sew through after turning the shell and my machine couldn’t hack it!

Stuff the edge pretty firmly

Stuff the edge pretty firmly

You can see the folded seam where the ends of the binding meet.

You can see the folded seam where the ends of the binding meet.

We’re in the home stretch now! Remember those upper arm straps we made back in part one? All we need to do is sew them in place! (And hey…if you made a pillow, you’re already done!) Grab your child (or dog, or whoever you’re making the shell for – I have to admit I’m pretty tempted to make a Koopa Paratroopa costume for my Corgi now) and pin the straps into place (think backpack). Hand sew them, and that’s it! Of course, I know there are red rings around Bowser’s spikes, but that’s just not a priority for me right now. I imagine it wouldn’t be too hard to add some red cord around the spikes if you just have to have it! I’ll see you in a few days for part three (Bowser’s head) – assuming I finish it!



15 Responses to “Bowser Costume, Part 2 – The Shell”

  1. Heather Says:

    How do you make head? I didn’t see a post on it. Love your costume!!!

  2. Heather Says:

    Yay..i cant wait to see it. How long has it taken you to make this? My 9 year old son want be bowser this year. I am worried i may not have enough time to complete the costume.

    • VisibleBlue Says:

      I’m not gonna lie – it’s taken a long time because there’s a lot of hand-sewing. I spent a long time engineering it too. I think I’ve been working on it for a few weeks, but it’s been a few hours here and there.

  3. Dawn Says:

    I love this – it’s what my grandson wants for Christmas and I am determined to get it done but I can’t find the head??? Do you have the directions for the head?

  4. Mandy G. Says:

    Any ideas on changing the shell up into a teenage mutant ninja turtles on?

    • Mandy G. Says:

      oops, I meant any ideas on changing this into a turtle shell? XD

      • VisibleBlue Says:

        Yes! I would just do the border in the same fabric as the main shell (so it’s all green) and omit the spikes. If you’re doing a TMNT shell, you could make the border small (no need to stuff) and try to emulate the quilting pattern (instead of hexagons, maybe just a large open area in the center and rectangles around the perimeter?) Depending on which turtle, you could use brown straps with buckles, cross-body, as well as a brown belt to keep it on instead of the black studded straps.

  5. Chris Says:

    Hey, I didn’t see any instruction on what to do with the green fleece layer that goes on the inside of the shell… from your pic it looks like it adheres to the inside – did you glue it onto the concave part of the cardboard or something? Great job btw – you are genius, and you will make my son happy this year!

    • VisibleBlue Says:

      Nope, I didn’t glue it, but I imagine you could! Since it’s not visible while worn, I just left it. It looks flat until something presses against it. I hope your son loves it! :)

  6. […] Then came the shell.  I followed the instructions from the VisibleBlue tutorial. […]

  7. […] Another critical element to Bowsette is her shell, which of course comes from Bowser. This shell is perched on her back, and is primarily green, with a white outline and must include the famous white spikes. This is probably the most difficult part of the costume because there are not many already created shells out there for sale. Hands down the best one we’ve been able to find is on Esty (here), and it is an absolutely wonderful creation, but it does come with a price tag. Amazon also has a Bowser costume kit that you could purchase that comes with the shell, and the price is a bit more reasonable. Or if you’re really ambitious, you could always attempt to DIY and create your own Bowser Shell. […]

  8. […] used some guides via Pinterest and the Googles: (carboncostume and, and got to […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.