I had a pet tarantula for years, it was amazing how fast it was able to build and change the layout of its burrow. I didn't play with it, to avoid stress, but it was an amazing guardian for my place. You just have to tell people that there is a big spider in the bookshelf and they run away :)

I have a cat.The other day I thought she wanted to get on my lap because she was sitting on the floor staring at me, so I got a blanket and made a cozy nest for her. She gets up on the other side of the couch and proceeds to ignore me. She is nice though sometimes.