A couple of springs ago we started hearing strange sounds at night. Something like a rusty nail being slowly drawn from an old board, somewhere near our bedroom window. Spooky and unnerving. It would pass, but in a few hours we might hear it again.
As the days passed it got louder; we could feel the vibrations shake the house. Pretty freaky.
We started staying up to catch the noisemaker.
One night we spied a 'possum squeezing out from under our wooden porch. There was a gap between the concrete and the porch of less than two inches; we watched the whole structure move up and down as she slowly, painfully worked her way out.
Mystery solved but we were still curious so one morning I pried up one of the steps and there was Mama and her babies staring up at us with that frozen death rictus grin they use in extremis.
We burst out laughing and nailed the step back on.
Oh, and Mama had a open red gash on her back from wiggling in and out from her den. I had to admire such devotion to her litter, but after she vacated the premises we filled in the gap with a board and haven't heard from her or her kin since.