An Inconvenient Smell

For the last week, a mystery odor has taken over my kitchen. I'm not really sure what it smells like, but it is not good. My first thought is that it was coming from underneath the oven, but there was nothing under there that would cause it. Different members of the family smell it in different places. Sometimes it seems the smell has gone away for 1/2 a day but it always comes back. I thought perhaps an animal died in the kitchen somewhere. I cleaned under the major appliances, even disconnecting the dishwasher and pulling it out from under the counter so I could see if something was behind there (nothing). The smell is actually making me a bit crazy. Two days ago while sitting on the kitchen floor investigating, I decided I couldn't take it anymore and used a hammer to pry the front baseboards off of 2 of the cabinets. No, there was no dead mouse in there as I had hoped to see, but there was plenty of disgusting crap. Cobwebs like I had never seen before, sawdust, construction dirt etc., and thousands of dead bugs - mostly ants and rolly pollys. Despite the fact that there were about 500 of those egg sacs that spiders make, I did not see one single spider. There were no animal droppings or any evidence of larger animals being down there. Yesterday, while lying on the floor trying to vacuum it all out with the attachment hose, my hair got sucked into the main part of the vacuum where the brush spins around and some of it got ripped out. Today the smell is still there. Oh odor gods, why must you torture me?!