Kumbhakarna was an ancient robot, fearsome more-machine-and-less-human-like ‘humanoid‘.
Ravana used Kumbhakarna sparingly, meaning, only during very difficult battle-situations, and it instantly turned the tide in Ravana’s favour.
May be due to its high maintenance, it was made to sleep for a period of about six months and awakened only when need arises or when it has to be re-fuelled.

https://www.booksfact.com/technology/ancient-technology/kumbhakarna-the-ancient-robot-used-in-ramayana-warfare.html