So just a quick idea I had and couldn't find any other threads about it. A Mechanoid that joins your colony disguised as a human. It's very obvious that it is only there to spy and observe your behavior however it proves very useful in helping the colony as it has 10 points in every skill and doesn't need to rest or eat or play. However it is a ticking time bomb and can off in day, a month or even years and suddenly attack the other colonist. You can choose to attack it now or use it as a tool to help build the colony.