Brains of Morphoton

The Brains of Morphoton were responsible for enslaving natives of the planet Marinus within an elaborate illusion.  The Doctor, Susan, Ian and Barbara all succumbed to the illusion which caused them to believe that they were living in a luxurious utopia.  The illusion broke for Barbara and she discovered they were actually in a ruined, dirty city under the control of the Brains.  Brought before them, she was able to smash the jars which provided them with life support.