Mystery tool - Giant Key? Old Pry bar ? Trying to identify this thing!

Hi, there. I have this giant metal thing and I am trying to identify what it is. I found it in my dad's garage with a bunch of old, old tools. He doesn't know what it is, either. He bought it from a yard sale.

It's about 30" long and looks like a giant key... Or maybe it's a pry bar?

There are no apparent markings on the item.

Any assistance is welcome, thanks!