The knife itself is made of 1 1/2" PVC pipe, spray painted silver. The blade is made of thin wood, and sits in a black rubber end cap that I slit open with a box cutter. I think the part that's under the cap is what really makes it: I went looking at Home Depot to find something to mimic that grip part on a real knife, and almost cried real tears of joy when I found this 2" clear pipe with nylon reinforcements in it. It fits perfectly on the PVC, with no adhesive necessary!
I cut the stencil out for the logo on my Silhouette Cameo, then traced around them with pencil and hand-painted the logo on with black. It's a tiny bit wambly, because it's not easy to paint on that round surface, but I'm pretty happy with it.
What does one do with a giant X-acto? I'm going to use this for a prop in a costume I'm making, and then it's going to live in my craft room as decor.