Soft knife

For a card making class I went to recently, were were given a list of supplies to bring with us, and on there was one item, a "soft knife". I thought of a few things this could be, but thought I'd ask the experts at Michaels while I was there with a friend picking some of the other items off the list. We asked a nice middle aged lady, who got a second opinion before bringing us to a section and pointing out this item. 

I said, "oh a boner!" and I cannot explain in words the contrast between the amusing look the Michaels lady gave me to the horrified look my friend gave me. But hear me out, the above tool is also referred to as Boning tool, it's for running along edges to make them crisp looking.

When we got to the class, it turns out it was a different tool entirely, but that memory will be hard to forget.