NPC

In gaming an NPC is a non-playable character in the game, one that the players cannot control.  It was originally controlled by the gamemaster or referee, and then later the computer. In its current state it has predetermined and rather limited dialogue and can only function in certain predetermined ways.  An NPC can have an impact on the game but not in any kind of intelligent way.

So to be called an NPC in real life is an insult.  It means that you are the unthinking puppet of someone else, incapable of original thoughts and ideas and slavishly following a leader.  This insult gained popularity with Trump’s supporters in 2018 as they produced hundreds of grey-faced avatars representing political liberals as zombie-like slaves of their left-wing ideologies. These supposed NPCs were used to spread false information until Twitter suspended them.

And now there is a trend for NPC streaming - the streaming of videos in which someone pretends to be an NPC character in a video game, producing their characteristic stilted and sometimes nonsensical phrases and exaggerating to absurdity their strained unreality.