What did the servant of Eli's sons use to take meat from people's sacrifices?

Answer: A three-pronged fork

He plunged the fork into the pot, and the priest claimed whatever it brought up, treating the LORD's offering with contempt.

“or for the custom of the priests with the people. When any man offered a sacrifice, the servant of the priest would come with a three-pronged meat fork while the meat was boiling”— 1 Samuel 2:13 (BSB)