The term "OG robot" could refer to various characters or entities in popular culture, robotics, or specific communities, depending on the context. However, if you are referring to the earliest and most iconic representations of robots in media or history, one notable "OG" robot is "R.U.R." (Rossum's Universal Robots), a play by Karel Čapek written in 1920. This play is credited with introducing the word "robot" to the modern lexicon.
If you meant something more specific, such as a character from a movie, a video game, or another context, please provide additional details!