final boss
Noun
Meaning
(video games) An extremely powerful enemy that a player fights at the end of a campaign or story.
(figuratively, informal) The best or ultimate example of something; an epitome.
(figuratively, informal) An extremely difficult thing that one needs to finish or beat in order to complete some task.
Source: en.wiktionary.orgExamples
If trashy television was a video game, The Jenny Jones show would be the final boss.