* "Brian the Bachelor" (Season 4, Episode 1): This episode features a subplot where Brian gets fleas after visiting a dog park and Peter tries to get rid of them with a flea bomb.
* "The Cleveland-Loretta Quagmire" (Season 6, Episode 14): In this episode, Peter gets fleas and blames Cleveland for it, which leads to a feud between them.
* "The Cleveland-Loretta Quagmire" (Season 14, Episode 11): This episode also features a scene where Brian has fleas, leading to a comedic moment where Peter attempts to remove them.
While there isn't a "flea episode" per se, these episodes all feature fleas as a running gag or subplot, contributing to the show's signature humor.