You are very close. This smells like a universal adapter, with an output that can be set to one of six different voltages. The cross thingie probably is some kind of universal connector with several different sizes.
I did some surfing, and found this:
Is this what you have? In particular, does yours have the 9 volt battery connector as shown in the lower right corner of the photo?
1. Is the square cross at the end of the cord coming from the adapter, or is it a separate piece?
2. At some point, someone over there is going to have to figure out which contact os positive and which is negative. Universal adapters such as yours usually have a way to change this, either a small switch on the adapter or an inline connection you can unplug and reverse. Does hubby have a small voltmeter?
3. Next up we'll get into how this will connect to your zapper.