This is a plastic card-shaped guillotine I bought from a magic shop a long time ago. There's a hole in the middle of the stand, big enough for an arm to pass through. You have someone put their arm through the hole in the stand, then you pull out the card and lower it like a guillotine. Surprisingly, the card passes right through their arm. There are no instructions, but it has a double structure, and you can figure out the trick by pulling them apart.