Ghost in the Jar's character entered the household after Rick had a flashback to the barbecue, along with the dozens of other parasite characters. When Reverse Giraffe made his speech, he claimed that he once saved Ghost in a Jar's life in Vietnam. Ghost in a Jar was one of the last parasites to be killed, most probably because either he didn't move while the others were killing the parasites, or due to his size, he was mostly ignored.
Ghost in a Jar is a little green, glowing, translucent ghost who is a generic dome-shaped ghost with a wavy lined bottom. He has two stubs for arms in which the only potrusions are thumbs and he has dots for eyes and a little line for a mouth. He is always inside of a clear glass jar with a shiny golden lid. He has a very gargled and ghostly voice and he speaks with a surfer's accent.
Ghost in a Jar is very cool and fun-loving. He is best known for how he can appreciate the jokes and puns people tell no matter how cheesy, complex, forced, or unfunny they are.
- Apparently, the jar is also part of the parasite as it reverts into a pair of parasite legs after Rick shoots the ghost. Both the ghost and the jar seem to be harmlessly disconnected from each other, either due to an ability of these parasites, or due to a visual illusion created by the parasites.