Neptr

NEPTR is a robot Finn created solely to prank Jake; appearing in "What is Life?." He came to life when Finn became frustrated that NEPTR wasn't working and threw NEPTR out into the rain where he was hit with a lightning bolt. While this brought him to life, he wasn't fully functional, so 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 becoming slightly evil, but he also becomes powered up to full power.NEPTR, or N.E.P.T.R. which is an acronym standing for Never Ending Pie Throwing Robot." He is a pie-throwing robot Finn created and brought to life so he can prank Jake. He usually calls Finn "Creator". He is made up of miniature tank treads, a microwave, a tuning fork, loose wires, a computer chip and a soup can.

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.

Appearance
NEPTR is made up of junk pieces stuck together with tape. Finn drew a face on the soup can, presumably intending this to function as the face.Instead, the knobs on NEPTR's side act as his face.

Trivia

 * In the end credits for "What is Life?", NEPTR is listed in the credits as "N.E.P.T.E.R", though it is unknown as to whether this was his intended name, or if the E was placed there as a mistake.
 * Adam Muto stated that technically NEPTR is half prince which so far makes him the only prince/half-prince in the show thats not an imagination or story.
 * As said from above it is be possible that NEPTR is the prince of ice and goblins (due to the fact that the goblins still think that whisper dan is finn).
 * It is unknown where NEPTR gets the ingredients for the pies, or if he simply generates them out of thin air.
 * Nepter is much like the monster from Mary Shellys Frankenstien as both are brought to life by lightning and are made from salvaged parts.