Have you ever been adopted by someone else's pet?

What was the pet, and did it eventually go back to its own family?

We’ve had a cat visiting us regularly for the past year and a half or so. She’s very friendly, and I know for a fact she has a home down the street. I talked to her owners on the phone after we put a collar on her with our phone number to find out if she was a stray. We haven’t fed her for many months, but she still shows up on our deck every evening and stays until we go to bed. She tries very hard to get into the house, sits by the living room window and meows at us if we ignore her, and climbs all over us if we go sit outside with her. At this point, I’m wondering if she’ll ever leave or if she’d just take up permanent residence if we let her into the house. The other day, she left rodent guts on our deck. So, either she loves us or she’s really mad that we haven’t let her in.

What’s your not-really-my-pet story?