Marf

Marf is Robot's and Monster's pet. He was introduced in the episode "The Blimp." Apparently, Marf and his owners all like bacon, as evidenced when Robot and Monster feed Marf some bacon before chaining their fridge closed. In "How to Train your Marf", another cube is there, named Narf.

It should be noted that Marf might end up ruining Robot and Monster's lives.

He is voiced by Curtis Armstrong.

Appearance
Marf is a small, grey, cubic robot that has very simple facial features. Marf has 4 wheels that he uses for moving, much like Robot. Simply put, Marf is basically a tiny, gray, cubic car with a face.