Help ID this Unico tool - what is its purpose?

[Ed in Virginia]

Got this in a box of tools from an estate sale. Have no clue as to its purpose. Found one like it on eBay but the seller didn't know what it was used for either. Can anyone clue me in? Thanks in advance!

 

[RPH]

Key wrench. Can be used to open cabinets, plumbing valves and such. Was the early version of security.

 

[MShaw]

Looks like it is a bung wrench. Ebay listing call it "

Antique Pat Pend Unico Elizabeth NJ Bung Wrench Odd Form Shape Tool Oil Tank"​

 

[Private Lugnutz]

I have a 3D example that is one of the very few tools the missus allows upstairs because as an objet d'art it actually fits the rustic antique-y decor of our 1893 house.

 

[RTM]

Like part of a giant set of jacks. Looks nice there.

 

[Private Lugnutz]

Thanks. It does resemble a giant jack. I didn't think about that before.

The interesting thing about these old "utilities" keys or bung wrenches is how many different shapes the male ends took, implying just as many different identical but female openings. I have a few of them, one similar to Ed's and a few others with only two ends, and they only have a couple common shapes among them. Ed's and mine only appear to have one common end (the cruciform, or chamfered square), for example. That goes to RPH's point about security.

 

[bmwrd0]

A giant jack would be called a caltrop.