I purchased a Guardians of the Galaxy NERF gun that came with a mask intended for kids to play pretend with. Being one to want usefulness out of all of the set, I decided to upgrade the mask for me to wear for Halloween.

Full disclosure, I am a very petite woman, so these directions may not work for a full-sized adult male. My partner was able to wear the mask for short periods of time, but I was much more comfortable.

You could also use these same steps to modify less than stellar masks included in store-bought costumes.

You'll need:

A store-bought mask or homemade mask without eyes
Red transparent/translucent fabric or plastic
Glue (either hot glue, Elmer's, or epoxy)
1 coin battery
2 LEDs (preferably red)
Small amount of electrical tape
Scrap foam (could be optional, but improves comfort significantly)

Step 1: Cut Fabric and Glue

I went looking for red transparent plastic material at my local art store (often used for tracing, etc.) but they were sold out, so I went with sheer fabric from the craft store's remnant bin. You'll only need a very small amount, so this is not worth spending a ton on. I ended up doing a few layers of fabric to get the look I wanted, so try on as you go. Because I was just using cheap fabric, I just used hot glue to tack the material in place, but should you use something different, use whatever glue you have on hand/is suitable for your materials.

Step 2: Add Foam for Comfort

I had a scrap piece of foam lying around from some electronic that was shipped, and I encourage you to use what you have on hand or can get cheaply. I cut a 2-3" rectangle the width of the mask, glued one edge in place and then used a utility knife to cut out the eye holes. I tried to the mask and ended up making some cuts diagonally to get a better fit, and added a piece to protect the tip of my nose. You don't have to worry about this looking neat because you'll be the only person who sees it.

Add a little cut in the foam between the eye pieces, and this will house your battery and LEDs.

Step 3: Light It Up!

Attach your LEDs to your coin battery, adjusting their angle so one LED will go over each eye hole. You may need a friend to help you get the placement right.

(Pro Tip: When you look at an LED, the longer leg is the positive side)

So that you don't blind yourself while wearing the mask, put a small piece of electrical tape on one side of each LED and have that be the side pointing towards your face. You can also use the tape to keep your LEDs in place.

Slide your battery and LEDs into the slot you cut in your mask. The battery should power the LEDs for up to 2 weeks continuously, so I chose not to permanently close the slot so I would have the ability to replace the battery later. You can see in my photo that I hadn't figured out the trick with the electrical tape eye protection