Korst Gogg Thek Lutiven-Day Slitheen

Hal Go Hetch Lutiven-Day Slitheen was the son of Kist Mag Thay Lutiven-Day Slitheen. He was part of the operation of a family Slitheen to turn off the Sun. He had posed as the fat kid loser, Carl. When Sarah Jane Smith intervened, Hal Go Hetch had teleported away as the machine failed, killing the rest of his family. (SJA: Revenge of the Slitheen)

He later appeared (disguised as Nathan Goss, a child prodigy), allied with the evil Mr Smith and a few surviving Slitheen with another plan to destroy the Earth. He wanted revenge on Sarah Jane Smith for killing his family, and was involved in the kidnapping of Luke Smith. (SJA: The Lost Boy)