Had me an unexpected visitor last night -- a little possum found its way in through the cat door. Too dumb to figure out how to get back out so I had to open the front door and shoo it. Wish I'd thought to take a picture first!
I don't think a full-grown possum would fit through the cat's entry. It used to be a little wider but I had me a small raccoon come through a couple years back and nailed up some boards to prevent that. Since then, I've only had to worry about visiting kitties coming in for a free meal.
Y'know, I really oughtn't leave food out at night. I can fill their bowls in the morning; they're always waiting anyway. But then, I wouldn't get to enjoy all the wildlife!