Here's the breakdown:
* The Initial Incident: Owen, the team's medical examiner, is attempting to revive a woman who has been transformed into a Cyberman. During the process, he starts hallucinating and sees visions of his deceased wife, Gwen, who asks him if he's ever tried jellied eels.
* The Recurring Gag: After this incident, Owen develops a peculiar aversion to jellied eels, constantly referencing them in various situations. He expresses disgust and even paranoia about the food, making jokes about "the eels getting him."
* The Significance: The gag serves as a humorous reminder of Owen's traumatic experience, highlighting his vulnerability and the lingering impact of his loss. It also adds an element of lightheartedness to the otherwise serious and often dark themes of the series.
* The Later References: The "jellied eels" reference resurfaces throughout the show, even years later, most notably in the episode "The New World" (Season 3, Episode 8), where Owen finally faces his fear and even tries jellied eels with surprising results.
The joke plays on the typical British stereotype of jellied eels being a strange and unappealing food, further adding to the humor. It's a playful and memorable element that showcases the show's unique blend of dark humor and science fiction.