Overseer Tidewrath was a naga boss in The Underbog of Coilfang Reservoir. He was removed shortly after the Burning Crusade was released. When you'd reach the top of the staircase and were able to see him, Ghaz'an would start climbing up the platforms to go and eat the Overseer. If you reached him in time and killed him yourself instead of Ghaz'an, you would be rewarded with nice loot. Ghaz'an could always be killed afterwards.