Make a dog mermaid costume using a cardboard box, felt, and Mod Podge Mega Glitter! This is so easy and your pet will look so cute.
Skills Required: Beginner. Even if you’ve never crafted before, this is pretty easy. You’re cutting a box, felt, gluing, and applying Mod Podge to felt.

Are there any fellow Amazon Prime members out there? I swear that everyone in my neighborhood belongs to Amazon Prime, because there’s a van in here every single day delivering goodies!
Amazon Prime is probably my favorite membership of all time, and this year I was inspired to make a costume with one of their boxes . . . also known as a “boxtume!” If you haven’t heard of a boxtume, you’re in for a real treat.
This was my chance to develop a creative costume using an Amazon Smile box as well as some additional crafting supplies. If you haven’t gathered from the photos above, I used an Amazon Smile box to create a mermaid costume for my pug. It turned out blingy and fantastic if you ask me!

You can make this mermaid boxtume for either a dog or cat. It makes for such a cute photo shoot, and may I suggest having plenty of treats on hand to show your pet how thankful you are for such a fun photo opportunity. Here’s how the costume was made!
Mermaid Dog Costume
Gather These Supplies
- Cardboard box in a size to fit your dog
- Felt sheets – you can make your mermaid any color your like; I chose blues! Get enough sheets to cover the box (for a small dog, I used 8 sheets)
- Adhesive glitter foam – 1 sheet for the tail
- Hot glue gun and glue sticks
- Mod Podge Mega Glitter or Extreme Glitter
- Scissors
- X-Acto knife
- Pen

The first step is to fold your box into its shape and estimate where you want the hole for your pet’s head to go. Draw the shape with your pen.

Use an X-Acto knife and/or scissors to make the hole. Try it on quickly over your pet’s head and make any adjustments as needed.

Depending on how tall your pet is, you may need to cut some length off of the box. We cut about 2 inches off the bottom of the box, and also removed the flaps with an X-Acto knife.

Tape up the box to seal it closed. The tape we used lists all the awesome benefits of Amazon Prime. We use the video streaming every single day! Around this time of year we’re binge watching Halloween movies, of course.

From one of the flaps that you removed from the box, create a mermaid’s scale. Ours was about 3 inches across the top and then 2 1/2 inches long. You can make the scales any size you like, but larger makes the costume come together more quickly.

Use the template you just created to cut your scales from felt! You’ll want to use various colors of felt to get the “mermaid look.” We used shades of blue, but mermaids can be any color, or so I’ve been told.

Use your hot glue gun to apply the scales to the box, starting at the bottom. Work your way all around the box, applying scales. When you’ve finished a row, you can trim the last scale with scissors as needed.
Then layer the next row. You can use the same color or a different color. Keep going and layering as needed, with your hot glue gun. Work all the way around the box until you get to the top. When you do the top of the mermaid boxtume, you’re going to work from the head hole down toward the tail.

Your boxtume is nearly complete, but it needs a little extra something! A real mermaid would have it no other way. You should add a little Mod Podge Mega Glitter or Extreme Glitter to the end of each scale with a paint brush.

This is how your finished Mod Podged boxtume will look. Never fear, that Mod Podge is going to dry clear, leaving the pretty glitter behind.

While your boxtume is drying, use your sheet of adhesive glitter foam to create the tail. Draw a tail on the back of the foam. You can afford to mess up because no one is going to see the back of the sheet . . .

To insert your tail, pull back some scales on the back and cut a slit with your X-Acto knife. Insert the tail and then remove a little bit of the paper to expose the adhesive on the sheet. Fold that part over and stick it to the boxtume to secure.

Now all you need to do is stick your pet in the boxtume! You can make adjustments to the boxtume so that your dog can walk, like cutting out a portion in the back for leg movement (if they need it) or attaching a piece of ribbon underneath to secure.

May I recommend a blue dog wig to complete the dog mermaid costume?

I think my piggie looks super cute!

This dog boxtume is SO easy to make. It was quick too – dry time for the Mod Podge was the only waiting time.

Who knows? The next time you hit the beach, you may see a mer-pug! They are such mythical creatures and have only been spotted in the wild a few times . . .

What do you think of my dog boxtume? I’d love to hear in the comments! You can use Amazon Smile boxes to craft other Halloween items too . . . like DIY treat containers, masks, and haunted houses. There’s no end to the possibilities!
If you enjoyed this costume, check out these other costume posts from this blog as well as my other blog DIY Candy:
linda smith
Tuesday 30th of October 2018
This is SO amazing, Amy!! Love it!
Toni
Monday 29th of October 2018
Oh my gosh this is the best doggie mermaid I've ever seen. This costume is awesome!