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/butcher.gif) chopwood.
Well pulled out the nail planted whit my herbs and scrweded out the rest of the new screws.
Chopped the board so found nothing wierd under it either just more wood.
this nail and board was playing whit us LOL.
Well i sure as hell cant explain it.
But for public healt resons i had to get rid of it too many ppl hurt them self and a bloody floor aint pretty when girls come over...T
hou when i think about it we have blood all over the place anyways lol...
(IMG:style_emoticons/default/drugs.gif) (IMG:style_emoticons/default/blowup.gif)