Final answer:
The correct term for a stone-like mass that forms around a foreign object in the intestines of a horse is an Enterolith.
Step-by-step explanation:
The term that describes a stone-like mass that forms around a foreign object in the intestines of a horse is B. Enterolith. Unlike renal calculi, which are stones formed in the kidneys from the crystallization of minerals in urine, enteroliths are formed in the intestines. Due to similar formation processes, it's clear how the term could be misconstrued with kidney-related terms like renal calculi or urolithiasis, but they are distinct phenomena with enteroliths being specific to the intestinal tract.