Mire Beast

Mire Beasts were octopus-like creatures native to Aridius.

History
They originally lived in the oceans, but these dried up, forcing them into the Aridians' cities in search of food. The Aridians kept out the Mire Beasts by walling off and blowing up the portions of the city infested with them. (TV: The Chase)

Circa 59,000 BC, the Gubbage Cone empire kept Mire Beast fighting pits. (PROSE: The Crystal Bucephalus)

When the First Doctor visited Aridius, one Mire Beast attacked Ian Chesterton and Vicki Pallister. (TV: The Chase)

Poached leg of Mire Beast was served at the Bumptious Gastropod. (AUDIO: My Dinner with Andrew)

When the Daleks later attacked Aridius, they disturbed the Mire Beast, including the Mire Colossus. The Mire Beasts were destroyed, allowing the Daleks to destroy the Aridians. (PROSE: The Sagarro Desert Storm)

Behind the scenes

 * The description of the Slyther in Terrance Dicks's novelisation of The Dalek Invasion of Earth as being "a vast lumpy blob of a body, powerful flailing tentacles, two tiny deep-set eyes shining with malice..." (quote, page 101) is actually that of a Mire Beast. It would appear that the BBC sent Dicks the wrong reference photograph.