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) Similarily, the Tenth Doctor was once heard to curse "for the mists of Clom." (PROSE: The Krillitane Storm)
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, much to the Doctor's bewilderment, suggesting the planet to have no real value. (TV: The Stolen Earth) as part of Davros's plan to detonate the reality bomb. This was stopped by Donna Noble, and Clom and the rest of the planets were subsequently back to their proper places. (TV: 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)