A doorbell pull?? What's on the other side of the door?

nothing, this thing is just mounted to the wall

Hmm....meant to be up when in use (whatever use that might be!) and down when not in use. Has holes for drainage...?
Any evidence of old wax on it?...like candle wax?

no wax, I was thinking candles too

One would not put a lighted candle on that shelf. It is too pecarious. Its made more like the trip treadle of a mouse trap. The shelf will fall at a slight disturbance. Maybe it is an intrusion alarm, or to announce that a pet has passed by.

Obviously the mounting screws aren't old so it may have been from someplace else. How old is the house it's in?

Looks like part of a leghold trap - the part the animal steps on.

Why it's screwed to the woodwork, ???

item was found at a yard sale, friend mounted it on wall. We have no idea if its supposed to be mounted on a wall or not.

The half crescent shaped part looks like the top from a bait box. I think it's something that's been made up.

yea could be something someone made. Interesting piece