Twelve is an inhabitant of the planet Hm Hm Hm who Mork swaps bodies with as part of his Vacation in the S2 episode Mork's Vacation.
About[]
Twelve hitting on Mindy
Twelve, a native of Hm Hm Hm, has, in his natural form, 6 arms and a propeller. And arrives into Mork's body after his previous cat inhabitant has vacated Mork's body, where he immediately indicates his complete lack of boundaries, grabbing Mindy and kissing her, and continually grabbing and harassing her despite her telling him to keep his hands to himself.
He is massively oversexed with no boundaries and an interest only in partying and fine things. Disparaging of Mork's 'wrappings' he leaves the apartment and purchases an entire (Travolta-esque) wardrobe, along with picking up two girls and champagne, and yet fully expecting Mindy to join in the partying, hitting on both Jeanie and her mother having returned as the Da Vinci's have arrived.
Heading up to the attic to party with his two pick ups, his stay is cut short, when Mork cuts his stay on Hm Hm Hm short, Mindy finding Mork's shell of a body awaiting Mork's return