Horrible Gelatinous Blob, often referred to as H. G. Blob, is a good-natured creature, unless he is upset about something such as problems at work or a sad movie. Then he becomes prone to violence at the slightest provocation. This usually ends with him swallowing the offending party.
In "The Series Has Landed", he appears as an actor on a commercial for Planet Express. However, in 3002 during The Route of All Evil, he doesn't appear to recognize Professor Hubert J. Farnsworth or Hermes Conrad before, during, or after beating them to a pulp. Also during that episode, he mentions he worked at a factory, but they introduced computers, causing him to lose his job and become stressed. He appears again in "Future Stock" as a stockbroker, and then as a member of Fathers Against Rude Television (F.A.R.T.) during "Bender Should Not Be Allowed on Television". In "Bender's Big Score", he is seen as the face of the Earthican $20 bill. Horrible is seen in "That Darn Katz!", frying a hobo, Gus, on the side of the street, and attended the 100th Delivery Party, being the first guest to have entered the Planet Express headquarters in "The Mutants Are Revolting".
- Peter Avanzino, director, stated, "Horrible Gelatinous Blob is a pain in the ass to draw."
- The spelling of his name as "H. G. Blob" may be a reference to H. G. Wells, an English author now best known for his work in the science fiction genre.
- In "The Thief of Baghead", it is mentioned that Horrible attempted to have botox treatment, but it ended in disaster. This has become a subject of interest for Us People magazine.
- "The Series Has Landed"
- "The Problem with Popplers" (Non-Speaking Cameo)
- "The Route of All Evil"
- "Godfellas" (Voice Only)
- "Future Stock" (Cameo)
- "Bender Should Not Be Allowed on Television"
- "Spanish Fry" (Deleted Scene)
- "That Darn Katz!" (Non-Speaking Cameo)
- "The Mutants Are Revolting" (Cameo)
- "The Futurama Holiday Spectacular" (Non-Speaking Cameo)
- "Saturday Morning Fun Pit" (Cameo)