|"Arthur's Cousin Catastrophe"|
|Number in season:||9b|
|Original Airdate:|| October 17, 1996|
January 16, 1997
|Written by:||Terence Taylor|
|Storyboard by:||Jean Charles Fink|
Arthur does his best to avoid his annoying cousin, Mo, at a family reunion.
Arthur's family is getting ready to host their annual family reunion. Just then, Arthur's Aunt Loretta, Uncle Bud, and three cousins: Monique (who usually goes by the name of "Mo"), Ricky, and Loretta's daughter arrive at the front door.
Loretta says that Mo has a surprise for Arthur and then Arthur has flashbacks to past reunions: When Arthur was 5 years old, Mo started the trouble by putting him on a lawn sprinkler; when Arthur was 6 years old, Mo practiced her judo moves on him; and when Arthur was 7 years old, Mo dressed him up as a baby by putting a bonnet on his head, a pacifier in his mouth, and a cloth diaper with a pin over his pants, and placing him in a stroller, causing everyone to start laughing in front of him.
Arthur then screams and starts to run away from Mo. Outside, Arthur hides in a tree to get away from Mo, who he claims is ruining his life. As Arthur gets down from the tree, Cousin George tries to show Arthur a comic book called Spider Guy, but Arthur starts running away because he thinks Mo is approaching him.
As Jane is grilling, Loretta walks over to the grill and shows Jane the Flip'omatic, a three-headed spatula. As Loretta is demonstrating the Flip'omatic, she puts the three blades underneath the hamburgers, and then flips them. The hamburgers fly high into the air and land on Mr. Haney.
While Jane and Loretta are still grilling, David announces a sack race. Just then, he spots Arthur, who is still trying to hide from Mo, and asks very loudly through his megaphone if Arthur wants to join the sack race. Arthur starts stammering excuses about why he can't, but then he spots Mo approaching, so he grabs a sack and begins hopping extremely fast. Arthur ends up winning the race, leaving Uncle Bud marveling at how fast Arthur is "for a little fella," and Ricky angry about losing. Ricky then throws a fit after losing by throwing his cap off of his head and stomping on it while still in the sack.
Jane and Loretta continue lowering the notch of the Flip'omatic to get the hamburgers done. Then, everyone starts eating dinner. Grandma Thora and her son-in-law, Arthur's Uncle Sean, are having a conversation with her mother.
They start having an egg race, and Arthur's great-grandmother wins the race. After that, they play charades, but Uncle Sean picks an obscure book nobody else knows. Then, David dresses as a clown and tells everyone it is time to play a game of musical shoes, but everyone is tired. A thunderstorm arrives, and it starts to rain hard, so everyone runs to get back inside.
At night, Mo starts playing the piano, revealing that this was her surprise for Arthur, and that she had taken up playing the instrument because she saw Arthur doing so; Arthur tutors her a little in the basics of playing the piano. Mo then admits she had been looking for Arthur so she could show him her skills with the piano; when Arthur says he thought she wanted to decorate him like a Christmas tree, or send him into space, Mo replies, "You? You're my favorite relative!" and then adds the only reason she comes to these "dumb" reunions is so she can play with him. Arthur replies that he's glad it's just the piano this time.
They start playing a jazzy tune together, which attracts all of their relatives into the living room and they dance along. Uncle Bud mentions that despite the weather, this has been a great reunion. Then we see the outside of Arthur's house but then we scroll up and see that's it's no longer raining and we see a full white moon in the sky and then the picture fades.
- Uncle Bud (debut)
- Loretta (debut)
- Thora Read
- Thora's Mother (debut)
- Cousin George (debut)
- Uncle Sean (debut)
- D.W. Read
- Francis Haney
- Kate can be seen next to the table when Arthur views a wide angle of the yard through his binoculars. She is absent throughout the rest of the episode.
- Arthur's Bionic Bunny binoculars has a special "DANGER" detector that goes off if spying on a person he has had a negative influence on or if someone appears out of nowhere.
- Spider Guy is a parody of Spider-Man.
- Musical Shoes is based on Musical Chairs.
- D.W.'s guess as to which bridge her uncle's charading is "London Bridge is Falling Down," a children's song.
- In the flashback of the reunion where Mo dresses Arthur as a baby from one year prior, Arthur's wearing glasses. However, he started wearing glasses in "Arthur's Eyes" during his second grade school year and the current family reunion is meant to take place in the summertime shortly before Arthur goes back to school and begins his third grade school year.
- In the flashback where Mo dresses Arthur up as a baby, the diaper disappears in the later shot as the scene ends.
- When Arthur and Mo play the piano together, some of Arthur's fingers go through the keys.
- When Arthur was going to the freezer he got buried in snow in the next shot all of the snow on him was gone.
- Main article: Arthur's Cousin Catastrophe/Gallery