The Slitheen-Blathereen are a family of Raxacoricofallapatorians who were created when the criminal Slitheen Family intermingled with another Raxacoricofallapatorian family called the Blathereen. They take after their Slitheen relatives and are criminals whilst they look down on their Blathereen relatives seeing them as weak and feeble.
Two Slitheen-Blathereen named Leef and Tree appear in The Sarah Jane Adventures episode The Gift who at first pretended to be peaceful Blathereen, but after revealing their true nature, they claimed to be much worse than the Slitheen and wished to turn Earth into a Rakweed farm. Unlike the Slitheen, Slitheen-Blathereen do not wear skinsuits but strangely wear compression field collars which Slitheen wear to fit into skinsuits for reasons yet unknown.
Slitheen-Blathereen resemble Slitheen however whilst Slitheen have green skin, Slitheen-Blathereen have orange skin.
- Leef Apple Glyn Slitheen-Blathereen
- Tree Lorn Acre Slitheen-Blathereen
- Originally, another Raxacoricofallapatorian family called The Rackateen were to appear in the series, but were scrapped and their costumes were instead used for the Slitheen-Blathereen.