I came across a Mountain Backpack, at the time of finding it I was wearing a SMERSH backpack. When I put the Mountain Backpack on I then proceeded to drag the SMERSH into the Backpack, once highlighted I accidentally clicked SWAP instead of ADD. What resulted was a SMERSH on my back and TWO Mountain Backpacks on the floor. I tried to recreate to make sure if I had done what I thought I had but I and am not 100% sure if it worked or not but there were other Backpacks downstairs of the same colour. There were no items in any of the Backpacks, not that I could see anyway.