Doctor Nefarious is a fictional character and the main and most prominent antagonist in Insomniac Games' Ratchet & Clank video game series.

In the series, Dr. Nefarious is a robotic mad scientist and supervillain with a deep, distinct hatred for organic lifeforms. He is depicted as the arch-nemesis of Captain Qwark and later of the duo Ratchet and Clank. Throughout the series, Nefarious is always accompanied by his loyal robotic butler, Lawrence, who often proves to be much more shrewd than his pompous master. He has a famous trademark gag of that whenever he loses his temper or is put under extreme stress, Nefarious instantly malfunctions and freezes up, while radio waves of episodes from the fictional soap opera series Lance and Janice are broadcast through his mind, until he is whacked behind the head by Lawrence or someone else.