Mud Bowl / Gerald Moves Out - S2-E9
Revealing mistake: At the lunch room, the 5th graders threaten the 4th graders again. Gerald starts talking to Arnold. He and the dark-haired girl to his left are both noticeably overlaid onto the table, not behind it. About 20 seconds later, the same shot is back and they're behind the table as they should be. (00:06:00)
Weird Cousin / Baby Oskar - S4-E11
Other mistake: Stephen Viksten is credited twice for voicing Oskar.
The Aptitude Test / Oskar Gets a Job - S3-E9
Suzie: I gave you 100 dollars two days ago.
Oskar: Suzie, you know I had to use it to pay the phone bill.
Suzie: Oskar, they cut off our phone service this morning.
Oskar: I know, it's a terrible mistake. We should sue.
Suzie: Oh, Oskar, that just doesn't make any sense.
Oskar: Tell me about it. So, can I have the 50 dollars?
Suzie: I don't have 50 dollars, we've already spent my paycheck this week.
Oskar: What about your overtime?
Suzie: I work 20 hours a week overtime already, how many more hours do you want me to work?
Oskar: How about 25?
Suzie: OSKAR!
Downtown as Fruits / Eugene's Bike - S1-E1
Trivia: Eugene's bike has a "YOOJ" (pronounced like "Eugene" without the "een") license plate.
The List/Haunted Train - S1-E8
Question: Why did that boy steal Arnold's ball? Was that the whole reason he came to the park? He seemed awfully obnoxious and destined to ruin Arnold's day, just wanting more clarity. Thank you.
Answer: The episode doesn't really elaborate on who the kid was and what his motives were, so its pure speculation as to why he took it. Perhaps the kid could simply want a ball all for himself and decided to just take it, or was simply a rotten kid. The truth is the kid's motives are not important to the story other than it highlights Arnold was having a lot of trouble getting through the list.
Lummie ★