My first inclination was GET THAT OUT OF MY HOUSE! But quickly I decided to look up on the internet (so grateful for this invention - really - thank you Al Gore) and learned in a few minutes that it was a grub and had come out of the acorn. This is what I found:
It seems that inside most acorns there is a very tiny grub worm. After the acorn falls from the tree the worm eats its way out of the acorn. This little worm is a favorite food of flying squirrels, which are the most common squirrel in the Ozarks. You hardly ever see them in the wild because they are nocturnal, but there are millions of them around here. Anyway, you can tell that the worm has eaten his way out of the acorn when you pick one up because there will be a small hole in the acorn - that is where the grub came out of. And you can tell if a flying squirrel has had a little snack because the acorn will have been eaten into - the squirrel really doesn't eat the acorn itself, but rather chews into it until he finds the grub worm. Sometimes if you gather up a quantity of acorns and put them into a plastic bag or bucket and wait until the next day, you will see many of these little white worms in the bottom of the container - and many little holes in the acorns!
Anyway - my challenge to you is to go out and learn something new today. Something unique, maybe useless and silly - but learn some new little tid-bit. It's kind of fun :)
(These pictures and information were found on this website.)