I found this on the beach on the coast of the Gulf of Mexico in Mississippi, USA like 18 years ago... Thank you for your help!
On this occasion, I tend to disagree with Florin.
I can't say what it is, but the surface layer suggests that what we see is close to its original shape (minus extremities) - which looks rather bone-like (hints of scapula?). I can't imagine a man-made object with that shape.
How dense is it?
...Like bone or like stone or like plastic? (and does it float or sink)
Can you see any texture in the surface layer or the core?
(Is it granular or spongey, for instance?)