This is a story by Julio Cortazar, from the book Cronopios and Famas.
"Discourse of the Bear I'm the bear in the pipes of the house, I climb through the pipes in the hours of silence, the hot-water pipes, the radiator pipes, the air-conditioning ducts. I go through the pipes from apartment to apartment and I am the bear who goes through the pipes. I think that they like me because it's my hair keeps the conduits clean, I run unceasingly through the tubes and nothing pleases me more than slipping through the pipes, running from floor to floor. Once in a while I stick my paw out through a faucet and the girl on the third floor screams that she's scalded herself, or I growl at oven height on the second, and Wilhelmina the cook complains that the chimney is drawing badly. At night I go quietly and it's when I'm moving most quickly that I raise myself to the roof by the chimney to see if the moon is dancing up there, and I let myself slide down like the wind to the boilers in the cellar. And in summer I swim at night in the cistern, prickled all over with stars, I wash my face first with one paw then with the other, finally with both together, and that gives me a great joy. Then I slide back down through the pipes of the house, growling happily, and the married couples stir in their beds and deplore the quality of the installation of the pipes. Some even put on the light and write a note to themselves to be sure to remember to complain when they see the superintendent. I look for the tap that's always running in some apartment and I stick my nose out and look into the darkness of rooms where those beings who cannot walk through the pipes live, and I'm always a little sorry for them, heavy beings, big ones, to hear how they snore and dream aloud and are so very much alone. When they wash their faces in the morning, I caress their cheeks and lick their noses and I leave, somewhat sure of having done some good."