Garbage-bots. (COMIC: Garbage Day!)
Garbage-bots (or Gar-bots) were hailed as the answer to the disposal of human waste in the year 2423 on Earth. They were fully automated robots given the capacity to decide what was considered garbage. However, they decided that humans, being covered with germs, were garbage too. The Eleventh Doctor managed to re-program them in time to save the people they had collected and turned the Gar-bots against themselves. (COMIC: Garbage Day!)