  It is known that many Twitter users are bots, which are accounts controlled
and sometimes created by computers. Twitter bots can send spam tweets,
manipulate public opinion and be used for online fraud. Here we report the
discovery, retrieval, and analysis of the `Star Wars' botnet in Twitter, which
consists of more than 350,000 bots tweeting random quotations exclusively from
Star Wars novels.
  The botnet contains a single type of bot, showing exactly the same properties
throughout the botnet. It is unusually large, many times larger than other
available datasets. It provides a valuable source of ground truth for research
on Twitter bots. We analysed and revealed rich details on how the botnet was
designed and created. As of this writing, the Star Wars bots are still alive in
Twitter. They have survived since their creation in 2013, despite the
increasing efforts in recent years to detect and remove Twitter bots.We also
reflect on the `unconventional' way in which we discovered the Star Wars bots,
and discuss the current problems and future challenges of Twitter bot
detection.
