The Exterminator is a lonely vampire whose real name is unrevealed; as his job title implies, the Exterminator works as an exterminator, getting rid of pests for people.
In The Super Mario Bros. Super Show! live-action segment "Vampire Until Ready", Mario and Luigi, who are being annoyed by a bat which has gotten into Mario Brothers Plumbing, call the Exterminator to come and get rid of it; the Exterminator agrees to do this job, but only comes to the apartment after dark.
After a confrontation with the bat that is pestering them, Mario and Luigi believe they have captured it in a napkin. Just after Mario apparently captures the bat, the Exterminator arrives and is told by Mario and Luigi that he is too late, as the bat is captured. Preparing to show the Exterminator the bat, Mario shakes his napkin, and is surprised when nothing comes out of it. Left wondering what is going on, Mario and Luigi are informed by the Exterminator that they will all find out soon; after saying this, the Exterminator lets out a laugh and shows off his large, pointed teeth.
Afterwards, while talking to Mario and Luigi, the Exterminator tells them that their problem with the bat is serious and that he will give it extra special attention; after saying this, the Exterminator rushes away to look around. The Exterminator is called back a few seconds later by Mario and Luigi, who are being harassed by the bat. By the time the Exterminator reaches Mario and Luigi, the bat is gone. Asking Mario and Luigi where the bat is, the Exterminator is told that it flew away by Luigi and Mario. Apparently not satisfied with this answer, the Exterminator gives Mario and Luigi a funny look, which Luigi interprets as meaning he thought him and Mario are lying about the bat. After being reassured of the bat's existence by Luigi, the Exterminator decides to leave to go to the washroom. Once the Exterminator leaves, the bat returns to pester Mario and Luigi, who begin to yell for the Exterminator to return. It is only when the bat leaves that the Exterminator returns and, after hearing from Mario and Luigi that the bat had left, becomes annoyed. Proclaiming that he cannot waste his time chasing imaginary bats and that no self-respecting bat would hang around in Mario and Luigi's dumpy apartment, the Exterminator leaves Mario and Luigi. It is only when the Exterminator leaves that Luigi starts to become suspicious, wondering why the bat only appears when the Exterminator is gone and vice-versa. As Luigi wondere this, Mario, apparently coming to a realization, proclaims "Uh-oh!"
Later, after managing to successfully ambush the bat and pin it to the floor with a plunger, Mario and Luigi are surprised to see it change into the Exterminator. Managing to pull Luigi's plunger off his face, the Exterminator, believing himself to be unwanted, prepares to leave, only to be stopped by Luigi and Mario, who wonders why the Exterminator has done all this. Answering Luigi and Mario's question, the Exterminator reveals that he is a night person and that when he is awake, everyone else is asleep, so he never has anyone to hang around with and play sports with. Feeling sorry for the Exterminator, Mario and Luigi decide to be his friends and to go bowling with him, which the Exterminator is ecstatic about. Before they go bowling though, Luigi decides to take the Exterminator and Mario to the blood bank, where he believes there’s a nurse who is just the Exterminator's type.