We had a kitten that somehow got inside the furnace. Fortunately it was summer and the pilot light was not on. They had to take part of the furnace apart in order to rescue her. Never could figure out how she managed to get inside. My mother was not happy and as I remember we didn’t have any more kittens after that.
I had a kitten vanish from a closed kitchen. I eventually found him napping in the sleeve of my jacket...after opening every cabinet and moving the fridge.