I'm useful in some manner, however my designed purpose is....

[KeepinOldBolts]

...not what the former owner did with it as an angled chisel.

The maker is Bonney, the part number BS100. It is 17" in lenth with a smooth machined business end surface. The original end may have been ground off. My first thought was it was for wheel service of some type. It's stout, but not stout enough to pry a bearing race (you want to drive those out anyway). It could be a seal pry bar, as in an automotive front wheel application. The chisel point is angled correctly for that and the hump is about in the right spot.

I could go on with automotive guesses, but I'll bet someone has a Bonney catalog.

[rusty]

It's not all that old, the rubber handle is the same one that is on my 1/2 bonney breaker bar....

Bonney's prefix letters sometimes hint at what the tool does, for example BU40 is the BUshing service kit...But BS100 isn't in any of the catalogs I have....
(nor are there any BS prefix tools)

[KeepinOldBolts]

I've seen that handle grip before too. Somewhere I have a 1/2" breaker bar with that same rough chrome finish but a green handle.  I think under the greasy patina of this is a red/maroon color. I've not explored that yet. I was thinking the part number prefix BS as standing for Bearing Service, or Bearing Seal in the part number string.

[john k]

Looks like a tool to remove a dust cap from the front spindle of a rear wheel drive auto.   But usually those were a plier type tool.