I’m famililar with the common possum, but this opossum of which you speak has me mystified.
I don’t have any helpful suggestions beyond BE CAREFUL. I’ve seen a couple of pissed-off possums, and they can be vicious.
Try leaving a trail of cat food leading to the nearest exit.
If all else fails, use Cheer.
Maybe Cecil can smite the ignorant possum?
I had one in the kitchen.once. I trapped him between a coffee maker and the wall. He gave me a toothy snarl and I realized I didn’t know what to do with him. I let him go and he ran like hell and I suddenly realized where he go in. I covered the hole and he never got in again.
Later when skunks got under the house, we trapped them and a couple of opossums. You can get a trap at Lowe’s for under $50. 
Get a dozen cats and throw them in the room with thte opossum. Make sure you have a video camera.
I just about fell off my chair laughing at that.
But then it’s nearly 5am …
Poly Whooshed. Who’da thunk it?
Say bib—what happened to the hairy little mutant? Give us an Update!
Well, thanks for all the suggestions, I knew if anyone would be able to help me in my hour of terror it would be you guys. After the hair on the back of my neck finally laid back down, I closed off the laundry room and awited the return of the designated opossom wrangler. Of course, the fuzzy little bugger had returned from whence he came by the time reinforcements arrived, but we kept the room shut off and avoided it. I’ve called the company Laughing Lagomorph recommended and left a message. With any luck in a day or two, we’ll be a oposom free zone. Thanks again for the help.