That is a LoJack adapter/extension/passthrough, according to the part number on the label.
It is not an OEM part.
The black wire that it is hanging from is probably still attached to the LoJack/GPS tracker that was installed in the vehicle.

https://www.ebay.com/itm/394608997788

 

So then, do I just shove it back up there? I purchased the car used at 27k miles, so I did not install this piece.

 

You can plug it back into the OBD port - the white port at the top right of your second image - if you want to maintain function of the LoJack/GPS tracker that was installed in the vehicle. If the vehicle was just purchased, chances are very high that it is powering a GPS tracker installed by the dealership where you purchased the vehicle.

 

Thank you for the informative replies! I bought the vehicle last February, and on my first service the mechanics said they found something spliced into the car, I'm guessing it was this device. I'll have to see if there's a way for me to access the tracking information, bc it would be nice to have that incase the car is ever stolen. But if not, I will be removing it.