It's a nail puller. The jaws clamp onto the head of the nail by digging into the wood around the head when you bang it with the slide. Once it clamps under the nail head, you pull sideways using the short arm for leverage. I used them many times for tearing into a structure for repairs.
works very good for pulling staples on a barb wire fence (wooden posts). No going to town for new staples,
pull the old ones and recycle.
I remember as a kid growing up in Kansas the "hedge apples" those trees drop. They were a plentiful source of... uh... ammunition, shall we say, for adventures in general mischief making. The wood sure burns hot (like whoa!) and pretty too; assuming you like fireworks. I remember my dad hating the stuff but also, oddly, fashioning a pair of grips out of the stuff for his beloved S&W revolver. Go figure.That's is probably true unless.......... The fence posts are "Bodark" (Osage Orange). If the bodark posts age at all, you're lucky to use a new staple once let alone recycle it. Ha! Seasoned bodark gets harder than woodpecker lips! When we cut new posts, we tried to use them within a short time. Green posts were easier on your fingers and staples. Ha!