I don't know about the "sniper cube" or if cube is even what I'm thinking about but I found a red prairie dog target that was suppose to soak up all kinds of bullets without hurting it.
The one I got was a display model without a base. Didn't even have the packaging. The store didn't have any on hand so I talked them out of the display and built a base thinking I was going to prove them wrong, I could tear up anything.
I set the little sucker out there at about 100 yards and shot the crap out of it...........I was wrong, I can't tear it up. I was highly impressed. Its a heck of a lot of fun and takes less maintenance then my steel targets (actually it doesn't take any maintenance).
I'd like to find more and scatter them all over my back pasture.