Wookieepedia

Where did the garbage monster came from on the Death Star ? You know, when 2 garbage monsters love each other very much... The history of Dianoga, the monster in the Death Star sewers is intriguing :

Dianogas originated on the planet Vodran — discovered by the Hutts prior to the formation of the Galactic Republic — where the creatures evolved a form of natural camouflage to avoid the planet's large predators. Their bodies would become transparent when unfed.

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