Clom, also spelt Klom, was the twin planet (or sister planet) of Raxacoricofallapatorius.
Native species
Clom was inhabited by an intelligent species. (TV: Love & Monsters) At some point they had a Disneyland on Clom. (TV: The Girl Who Waited) They were members of the Raxas Alliance, along with Raxacoricofallapatorius, Clix and Raxacoricovarlonpatorius. (TV: The Gift) Despite this, there was an adversial relationship between Clom and Raxacoricofallapatorius. (TV: Love & Monsters) Clom was used in an oath by a Slitheen as "for the love of Clom". (TV: Revenge of the Slitheen)
Land prawns were a popular delicacy on Clom and was also enjoyed by Raxacoricofallapatorians. (TV: The Gift)
History
The "Abzorbaloff" was a native of Clom. (TV: Love & Monsters)
Along with twenty-six other planets, Clom was stolen by the Daleks and taken to the Medusa Cascade in 2009 as part of Davros's plan to detonate the Reality Bomb. This was stopped by the Tenth Doctor and the Children of Time, who sent Clom and the rest of the planets back to their proper places. After learning the planet was stolen, the Doctor questioned why anyone would want to take control of Clom. This suggested the planet was not a desirable military target. (TV: The Stolen Earth / Journey's End)
References
The Eleventh Doctor used Clom as an example to show that all observed planets had names, no matter how dull they were. (PROSE: Into the Nowhere)