21st century Edit
The Passameer-Day Slitheen tried to reduce the Earth to nuclear fuel in March 2006, but most of them were destroyed in a missile attack by Mickey Smith. (TV: World War Three, Boom Town) Around March 2007, the Slitheen took over a building company called Coldfire Construction and tried to destroy the Earth by shutting down the Sun with a loop of transducers built around the world by Coldfire. They would have used the profits from the Earth's remains to avenge their relatives and to buy a fleet of starcruisers to destroy Raxacoricofallapatorius' Grand Council.
In September 2008, Kist Magg Thek Lutiven-Day Slitheen tricked Luke Smith into making sure the machine worked properly after its trial run failed. As Luke's calculations didn't account for the Sun's energy being absorbed, the machine overloaded and was forcibly reset. Luke started to repair it, but his adoptive mother Sarah Jane threw him her sonic lipstick. Luke damaged the machine with the lipstick. Kist was accidentally killed in the confusion, but his twelve-year-old son Korst escaped. (TV: Revenge of the Slitheen)
In February 2009, Korst teamed up with two other adult Slitheen to seek revenge and make the Moon crash into Earth. However, when they were betrayed by Mr Smith, they helped Sarah Jane stop him. They then left the Earth. (TV: The Lost Boy)