It's a pharyngeal tooth from a large fish like a drum or a parrot fish.
The pharyngeal jaws are for grinding and also contain a pharyngeal mill, where larger and smaller teeth grind coarser and finer coral pieces. Fish like the Black Drum use similar teeth to grind bivalves and molluscs.
They are ideal for scraping and crushing the tough and calcified materials that make up the parrot fish's diet, coral skeletons and polyps, and algae-covered rocks.
The teeth are typically arranged in several rows, with each row containing multiple tooth plates. The outermost row consists of larger, stronger teeth, while the inner rows may contain smaller and more specialized teeth for further grinding and pulverizing food particles. This multi-row arrangement provides parrot fish with an efficient means of food processing. teeth of that kind are also found in other fish, and they are reinforced to handle high mechanical loads. https://www.sciencedirect.com/science/article/abs/pii/S1047847720301039