Gurnian

Gurnian was a swamp planet that once was the location of a Dalek base. The swamps were infested with vicious two-headed monsters known as horrorkons which were kept under control by a squad of Marsh Daleks.

In the 25th century, a ship was captured containing the two Humans Andy and Mary Stone. The Daleks stationed on Gurnian decided to cast their prisoners out into the swamps to see if the humans would be devoured by the horrorkons. Andy and Mary found out, however, that the horrorkons preferred a meal of metal as opposed to flesh, determined by the rather docile nature of the creatures toward them and the mutilated wreckage of a Marsh Dalek found nearby.

The duo used this knowledge to their advantage, leading the horrorkons toward their ship with metal scraps. The horrorkons promptly attacked a squad of Daleks investigating the ship, decimating them and allowing Andy and Mary to escape. (DWA: Monsters of Gurnian)

Around the time of the Great Civil War on Skaro, the Seventh Dalek Armada was defeated at the battle of Gurnian. (DWBIT: Dalek Wars)