


New minor character is treated like they've always been there and prominent for comedic effect
Ponce de Leon in Clone High was introduced as an old friend of JFK for the sole purpose of having him abruptly killed off for fake pathos in a parody of similar storytelling in teen drama.
Koogler was introduced as a Van Wilder style big man on campus in an episode of Community as a meta joke about popularity and a cameo for Mitch Hurwitz.
And, perhaps my favourite and most meta example, Rick and Morty has an entire episode about this trope called Total Rickall where the Smith household is infested by alien parasites that manipulate people by pretending to be important figures in their life and trapping them in flashbacks and clips.