A mystery

Do you watch Ask This Old House? They have a section where they pull out a random tool or gadget and ask "What is it?" and the guys go around thinking up ridiculous ideas for what it could be ("It's a lazy susan for Tommy's sandwiches."). It's super cheesy and I LOVE it.

I could use them right about now.

We have a bolt on our basement floor. It just sticks out of the floor, right in the pathway between the door and the washing machine. It has some sort of electromagnetic force field that draws your foot to it, which means there's a lot of swearing coming from the basement because I always step on it.

It didn't correlate to any parts on the old furnace, though it had been retrofitted for gas at some point, so maybe the original configuration used it?

Original furnace

Greg tried to unscrew it but the thing wouldn't move. It's all of one piece, which makes me think it was put there when the slab was poured.

See how it's right where you want to walk when you're carrying a load of laundry from the dryer?

Anybody seen anything like this is an old house? Is this a portal to hell? An important bolt for an underground natural gas line? Does it involve the post right there? Any ideas? My foot is bruised and sore and I'm ready to take a jackhammer to it.