Megaladon

These monstrous sharks were some of the largest predators in the ocean. They ranged in sizes of 20 to 65 feet (6.1 to 20 meters) in length,with the larger sizes being more prevalent in ancient times, and weighed between 10‒60 tons (9,100‒54,000 kg). Some were rumored to even reach lengths of 80 to 90 feet (24 to 27 meters).
https://forgottenrealms.fandom.com/wiki/Megalodon