Haunted Nail, dont know what to think about this Options

(IMG:style_emoticons/default/insane.gif) Now our house has been getting kinda funny(others say creepy but..) most things as sounds and things dissapearing and coming back
can be put on the account of curius beings but.
We have a nail in the door step to the living room that just keeps popping up the nails beside is not affected i have nailed it in around 10 times already and nailed in 1 on each side to verify its not the board moving.
I meen wtf a nail?
I know they move over the years and so but whitin 25 minutes max it pops up again slowly thou as its being pulled..
anybody got an explanation?

(IMG:style_emoticons/default/weird_thread.gif) Well for the fungus part we have some sort of wierd mushrooms growing in our boiler room..(they look kinda like brown goblin ears lol)
They pop up over night. (IMG:style_emoticons/default/zap.gif)
but as for the nail its now banged in a closet
and doing fine. So not the nail but to the intresting part the screws are also coming out but not as much just a little.
But i will see tomorrow i tightened them now.
But if they still come out i will rip that door step out and make fire wood out of it. (IMG:style_emoticons/default/butcher.gif)