The Slitheen-Blathereen family were a Raxacoricofallapatorian criminal family created when the Slitheen family and Blathereen family intermingled. While they were criminals like the Slitheen they considered their relatives "much much worse" but felt that they should have tolerance for them. On the other hand they had no respect for the Blathereen, believing them to be weak. The known members were a red-brown colour, as opposed to the green of the Slitheen.
Two Slitheen-Blathereen, Leef Apple Glyn Slitheen-Blathereen, and Tree Lorn Acre Slitheen-Blathereen had become addicted to Rakweed. They planned to cover the Earth with it, then sell it to others. Around 2009 they based themselves in Antarctica, Earth and managed to capture two Slitheen, in front of Sarah Jane Smith, Luke Smith, Rani Chandra and Clyde Langer. They pretended to be peaceful Blathereen and gave them Rakweed as a "gift". The Rakweed soon spread around London, infecting Luke along the way. Sarah Jane eventually arrived at their spacecraft by teleporting, but was captured by them. She was able to break out after learning of their plans and then escaped home. Mr Smith was able to destroy the Rakweed by using high-pitched noises of every electronic device in the area to destroy them. When the Slitheen-Blathereen followed them to London, Sarah Jane was forced to destroy them by activating the noise again, which caused the Rakweed in their stomachs to expand until they exploded, covering everyone in orange goo. (TV: The Gift)
Sometime after this events Sarah Jane Smith was kidnapped by the Slitheen-Blathereen. They told Rani Chandra that they would condemn Sarah Jane Smith to a life in exile unless Rani helped to grow the Rakweed until it would cover the Earth. To save Sarah Jane Smith Rani did as she was told. Sarah Jane was released but the Rakweed still grew and it would cover the Earth soon. Furthermore Luke Smith got infected by it's spores again. The Slitheen-Blathereen thought that they had won. (WC: Plants) Mr Smith and Clyde Langer had a plan to stop the Rakweed. They used Haresh Chandra's electric guitar to make the same sounds and vibrations as the school bell of the Park Vale Comprehensive School, which had destroyed the Rakweed before. The guitar sound broke the plants' communication methods and neutralised the Rakweed spores. This killed off the Rakweed and saved Luke's life. (WC: Sound)
The Slitheen-Blathereen had advanced technology. Tree Slitheen-Blathereen was capable of genetically modifying the Rakweed to grow even faster. They had a spaceship which was capable of remote teleportation and tracking of the growth of Rakweed in London. They used bracelets which could activate the teleports, fire lasers and hack into advanced computer systems. (TV: The Gift)
Behind the scenes
- The two Blathereen suits were actually left overs from an unused project in which the Rackateen would appear to Sarah Jane.
- A Blathereen appeared in a specially filmed trailer aired before the premiere of Series 3 of The Sarah Jane Adventures. The trailer had Sarah Jane and the gang coming across an old lady, a postman, and a teenage girl, with one of the three being a Blathereen in disguise. The viewer, having been given the sonic lipstick by Sarah Jane, had to choose which one they believed to be the Blathereen. The correct answer was later revealed to be the postman.
- A Blathereen appears in Level 6 of the online game, Think Before You Sonic!. It is armed with an energy weapon and fires at Rani, who uses her sonic tool (lipstick or screwdriver) to draw a line which blocks its attacks so she can make it to the TARDIS.