1 Samuel 2:13-14

13Now it was the practice of the priests that, whenever any of the people offered a sacrifice, the priest’s servant would come with a three-pronged fork in his hand while the meat was being boiled

14and would plunge the fork into the pan or kettle or caldron or pot. Whatever the fork brought up the priest would take for himself. This is how they treated all the Israelites who came to Shiloh.