My apartment has a bunch of living things in them. Some probably not invited, but some are quite welcome.
The biggest ones (aside from me) are the plants. As a single Bjarni, I have had to learn to water them so they don't get all droopy. I think I figured this before irreparable damage was done, I think they will forgive me.
However, the most numerous creatures in my apartment, at the moment, are probably yeast germs. According to random numbers I found in some forum on the Interwebs, there might be between 10 and 20 trillion of them in my apartment right at this very minute, hard at work on my behalf...
I try to keep them comfy and well fed at a balmy 30°C.