Strange objects were always popping up at our previous house, and here too we have some mystery objects from time to time.
This metal plate was under the gravel edging the front yard. At 12.6 ounces, probably came off of some heavy duty contraption? It’s about 5.5″ by 2.5″and a half inch thick. The main bit has t shaped wings, and the thin metal plate on the (back?) looks like it originally could slide off where that pin in the middle is. I might try to WD-40 the snot out of it and see if that will come off. The thicker plate on the other side is chipped.
I am going to put this on Reddit, someone on there will probably know right away, “Oh, that’s a ’54 Packard trunk lid counterweight! Someone probably slammed the trunk too hard, ejecting the counterweight and making the trunk lid not stay up anymore after that”