I guess he's not just playing dead. Cats won't touch opossums, it's a primal instinct. A large enough dog could do it. Maybe a fisher, fox or coyote if you have any of those in your area. Opossums, skunks, raccoons, all prefer to run than fight. But skunks and raccoons are frequently rabid, and in that condition they can be vicious and unpredictable. OTH, possums are almost never rabid. If there are rabid critters running around, you may have a worse problem than a stinky corpse. Make sure your pets are vaccinated. And be cautious about whatever lurks under your house.

I think I would have rigged up a fishing pole with a big hook and sinker and cast for it.