Technically a squirrel. But it lived in my friends backyard, so it wasn't really mine. LOL.
It was a baby squirrel that was separated from its mother. It was still partially blind (hadn't fully opened its eyes yet). It walked right up to me, and climbed into my arms. Turns out he had fleas (LOL), so we couldn't keep him in the house. We kept him in a big dog carrier until he could see properly. We fed him crackers, a few nuts, and some fruits. He was spoiled! LOL. We named him Crackers, 'cause he LOVED his crackers! Once he could see, we let him free, but he stuck around for a few weeks. We left the dog carrier in the backyard with the door open, and he would go back in it to sleep at night. Eventually he moved on, and left us. He lives in one of the trees near our house. XD Sorry for the long story, I just really loved Crackers XD.
Other than that, my African Dwarf Frog is the most unusual pet I've had. XD