We had a possum(s) living in a tall tree that overhangs the kitchen chimney. They would often fall down the flue liner and I'd come in to the kitchen of a morning to find one peering out of the glass window in the wood burner.
Spent many an hour chasing the buggers round the house if they've wriggled free from my gardening-gloved hands as I've evicted them into the back garden.
Not an issue now, possum-proofed the flue stack.
We're form the UK, the first time I heard a possum take off along the front veranda in the middle of the night I shat my pants! Wondered what the hell it was.