Mud

You may be looking for Multiple User Dungeon, a kind of computer program.

After rain, dirt would turn to mud. (PROSE: The Shadow in the Glass ^[+]Loading...["The Shadow in the Glass (novel)"], Loving the Alien ^[+]Loading...["Loving the Alien (novel)"]) Flooding had the same effect. This would make travel difficult, particularly on unurbanised soil. (PROSE: The Shadow in the Glass ^[+]Loading...["The Shadow in the Glass (novel)"]) Mud was slippery, (PROSE: The People's Temple ^[+]Loading...["The People's Temple (short story)"]) as well as sticky, (TV: "The Escape" ^[+]Part of The Daleks, Loading...{"namedep":"The Escape (3)","1":"The Daleks (TV story)"}) to the point where one's shoe could get stuck in it. (AUDIO: The Paradise of Death ^[+]Loading...["The Paradise of Death (audio story)"])

Rigel Seven had an abundance of mud, due to its rich soil and heavy rainfall. The local Rigellans appreciated this. (PROSE: Players ^[+]Loading...["Players (novel)"])

The core of the planet Androzani Minor was superheated primeval mud. When it approached Androzani Major in orbit, a mud burst occurred, bursts of boiling-hot mud, or as Peri Brown put it: "mud baths for everyone." There were mud barriers in place at the time the Sirius Conglomerate were there. (TV: The Caves of Androzani ^[+]Loading...["The Caves of Androzani (TV story)"])

In 3985, Bernice Summerfield and Camarina Lannic's expedition were attacked on Menaxus by mud creatures, but managed to escape with the dream machine. (PROSE: Theatre of War ^[+]Loading...["Theatre of War (novel)"])

"Alien mud" encountered by the Eleventh Doctor, Amy and Rory, consumed anything inorganic. (COMIC: The Moon of Lost Hope ^[+]Loading...["The Moon of Lost Hope (comic story)"])

Genetic sculptor Garg Ardoniquist genetically engineered creatures to make bricks out of mud with their heat vision. (COMIC: Stairway to Heaven ^[+]Loading...["Stairway to Heaven (comic story)"])

While defending herself, along with the rest of the TARDIS crew, against the Daleks, Barbara Wright thought to make mud from Susan's shoe, and blinded a Dalek's eyestalk with it. She described it as "very sticky and very nasty". This trick enabled Ian Chesterton to get inside that Dalek, to pretend to be one of them, allowing for their eventual escape. (TV: "The Escape" ^[+]Part of The Daleks, Loading...{"namedep":"The Escape (3)","1":"The Daleks (TV story)"}) Later, on the way back into the Dalek City, a swamp's uneven ground alternated between rock and thick mud. (TV: "The Expedition" ^[+]Part of The Daleks, Loading...{"namedep":"The Expedition (5)","1":"The Daleks (TV story)"})

Visians, an invisible species, could be observed if covered in mud. When made visible, they appeared "thin, bony, with two long, clawed arms, feet like birds' claws, and a narrow head with a beak." (PROSE: Mission to the Unknown ^[+]Loading...["Mission to the Unknown (novelisation)"])

The "mud" in the Zona Oscura was actually biomass that would allow lost ideas to exist. (PROSE: Party Kill Accelerator! ^[+]Loading...["Party Kill Accelerator! (short story)"])

Behind the scenes

• According to Inside a Skaro Saucer, one of the features in The Dalek World which, due to not being actual stories, are not considered valid sources on this Wiki, Mireoton was "the Planet of Mud".