Battery voltage drops to 5V with negative connected on a Ford Edge

Hey all, I hope this is allowed since this isn't Mopar related, but I've been racking my brain on this for a while now. My girlfriend's car is an '08 Ford Edge that I think has a parasitic draw, but I can't find it.

With a fully charged battery, after a few days the car will be dead in the morning. I can jump start it and it starts right up, voltage goes from almost zero to 12-13V within seconds. The battery is new, and while it used to hold a charge after jumping it, now it will drain down within an hour. That being said, I think the battery may be toast since it has been drained too many times.

I can charge the battery, and the voltage between the posts is high 12s, but the second I connect the negative terminal, voltage drops by more than half.

I've tried a parasitic draw test by disconnecting the negative terminal and touching my meter's probes to the negative post and negative terminal, setting it to the amps setting, and removing each fuse one by one to see if the number drops to zero. I removed every fuse in the car, but never saw the amperage drop.

What am I missing here? Bad ground somewhere?