This may be intended for cosplay purposes, but honestly, the Shrink Ray science weapon would look killer just sitting on your entertainment center. You know it's the truth.
You're going to want to get on this one early, though, since the gun is custom 3D printed and painted by one person through an Etsy storefront. So expect these to go quickly and time to run out if you want to get it by Christmas!
If you've got a 3D printer and are feeling a little adventurous, there are a number of 3D files for various The Outer Worlds weapons also up for grabs at Etsy.