Fragment of sculpture with finished sides and top. The top curved with a cylindrical shaped object modelled on top of it. Large scale cobra tail possibly? See Documentation for other related cobra fragments.
From Nubia (Sudan) Gebel Barkal, B500 doorway. 1920: excavated by the Harvard University-Museum of Fine Arts Expedition; assigned to the MFA by the government of Sudan.
Harvard University—Boston Museum of Fine Arts Expedition