This was the first Halloween that my daughter was able to come up with her own costume. For a while, it changed every week, then settled on "pumpkin." So, I used her pumpkin-shaped trick-or-treat bucket as a pattern to make her a wearable giant pumpkin costume. It took a couple weeks of spare time, but it turned out great.

The hat came off in about 30 seconds, and that was really the most complicated part. I'm not going to spend much time on it here, because she didn't wear it hardly at all. There are a couple notes and pictures in the last step if you are interested.

Step 1: Materials

Consumables:

Orange fleece, ~2 yds (I had a remnant, it was less than 2 yds)
1/2" upholstery foam, ~2 yds (only used 5ft of it)
cheap muslin, 1/2 yd would probably be more than enough (just using a few long strips of it)
orange or red thread (doesn't really matter too much, it stays pretty well hidden)
Black fleece, scraps
Black bias type, 3' or so
Black thread

Tools:

Cutting stuff (love my rotary cutter!)
Sewing stuff (pretty much need to machine sew this)

Step 2: Outer Shell

Cut 6 panels from the orange fleece.

For more information on the shape, refer to my Plush Ball project, it uses the same process:
https://www.instructables.com/id/Plush-Ball/

I was using remnants here, so I just made them as big as I could but still get 6 panels out of the fabric. That made it about 10.5" by 22". My measurements weren't perfect, and I was adjusting to fit the remnant, but the design seemed pretty tolerant to changes of almost an inch in either direction.

I didn't take pictures of the process for sewing together the fleece panels, but it is essentially the same as for the Plush Ball, above. Just don't close up the top and bottom. Also, if you save the last seam until after you add the foam, your life will be easier. I sewed all 6 seams before adding the foam, so it's not impossible, but it would have been easier to work with the foam if the fleece part was open.

Step 3: Inner Shell

Cut 6 foam panels to the same shape as the orange panels. You can cut large and trim back as necessary, but it's actually fine if they are a bit small. Here's a preview of what will happen when the edges are sewn together and the pumpkin is turned right-side-out:

Foam too big: The foam pops "in" and not "out", so it looks like the pumpkin has a dent in it.
Foam too small: The fleece has slight wrinkling, but the shell holds up well. (I didn't think it looked bad, so I erred on the small side)
Foam just right: Foam pops "out" and the fleece appears taught.

With a foam panel lain right on top of an orange panel, we are going to sew one straight stitch all the way down the center of the panels. Doing this for all 6 panels will make it look like we have 12 sections instead of 6 (which is good!).

Use the muslin cut in strips (about 1 1/4" wide) to keep the machine from getting caught up on the upholstery foam. I imagine a walking foot would be very useful here. I just have a standard foot, though, and the muslin worked fine for me.

Pin the muslin and the fleece to the foam panel you are currently sewing. Be sure to pin the fleece side outside of where you pinned the muslin side, you don't want to accidentally hit your pins when you can't see them.

Step 4: Constructing the Body

Once all 6 foam panels are machine-sewn onto their fleece counterparts, close up the last set of fleece panels if you haven't done so already.

With the pumpkin foam-side-out, use any color thread to whip-stitch the edges of the foam panels together. Leave a few inches free at the bottom, it helps make it easier to walk and to get the pumpkin on and off the trick-or-treater.

Initially, I thought it would be good to push the needle through the foam and through the fleece seam in the middle, but I don't think it's necessary. If you do decide to go through the fleece, be sure to only go through the excess part of the fleece seam, not the good part. If you go through the good side of the seam, your stitch will show up on the outside when the pumpkin is flipped right-side-out, and it won't look great.

When the edges are sewn, the pumpkin will have structure. Use a model to get proper arm hole placement. With 12 segments visible on the pumpkin, I ended up with 4 segments in front, then the arm hole segments, then 6 segments in back. That seemed to work pretty well.

The arm holes are about 3 inches from the neck, and about 3 inches long, and about 2 inches wide at their widest point. We tested quite a bit between cutting to make sure they wouldn't be too snug.on the trick-or-treater's arms.

Step 5: Finishing

Now the finishing touches. I had some leftover black bias tape from another project, so I used it to clean up the arm holes and neck hole. No need to worry about the under-side, no one will see that.

The face is just made of scraps of black fleece, cut to match the reference pumpkin. I sewed them on using a whipstitch.

Step 6: Trick or Treat!

I also made a hat (seen on the cover photo). Use the scraps sewn together for the pumpkin top. Finish the edges by folding over once and sewing a straight line. Add a stem using a little scrap fabric sewn into a tube and filled with polyfil, hand-sewn to the top of the hat. A piece of elastic will keep it attached to the child's head for about 30 seconds.

That's why I'm not spending more time on the hat, it was more effort than it was worth.

Also, the unfinished bottom of the pumpkin is visible after all... but I promise you won't notice until you start cropping the photos.

The costume was fine for her to walk around in, and was light enough that she didn't get tired right away.

Special side bonus, it was really easy to keep track of her when she looks like a bloated traffic cone!