I had our cat knock over a feeding tub(with lid on) and a very small corn got loose in my shop. Try to imagine every tool, compressor, drill, etc. that I have as well as all my snakes and their gear in one room. LOTS of places to hide. What I did was:
a) took every object on the floor, including anything she could climb and inspect it then
b) move it outside the doorway...one by one.
I did this making my way around the room and about 3/4 of the way I get to my biggest bookshelf(old one) that houses my paints, chemicals etc. Needless to say it was very heavy and is located in a corner. I almost skipped it. Luckily I moved it away from the wall with the help of a friend and there was my corn against the wall. If this is inside and there are air vents on the floor, check those too. As long as you know the lil' bugger was confined to the room, you have a good chance of finding him.
Good luck! :cheers: