| This minifigure has only appeared in video game(s)|
Although this article is about an official minifigure, it never existed in physical form or appeared in any official LEGO sets.
He came to life when Finn became frustrated that his shoddily-assembled "robot" was not working and threw the creation out into the rain where he was hit with a lightning bolt. This brings NEPTR as we know him to life, though he is not fully functional. Finn took him to Ice King's palace to use the villain's lightning bolts to fully charge him. When he was hit with Ice King's lightning bolt during the resulting battle, part of NEPTR's personality was changed to a desire to collect princesses causing him to become slightly evil, but he also becomes powered up to full power. Neptr admires Finn's pranks and has decided to keep Finn as his companion, and has also decided to prank Ice King hardcore. However, he is shown to have some compassion, as he says goodbye to the (unconscious) Ice King before leaving with Finn, causing Ice King to shed a tear. After this, he and Finn throw never-ending pies at Jake.