Full Moon / Student Teacher - S4-E1
Revealing mistake: Full Moon: When Principal Wartz tells Arnold to name the boys who exposed themselves, as Arnold says, "I can't do that, Principal Wartz," his mouth briefly disappears. (00:02:42)
Simmons' Documentary / Big Bob's Crisis - S5-E20
Revealing mistake: Simmons' Documentary: When Phoebe asks Mr. Simmons, "If we're required to do book reports, do we need to choose a book?", her mouth disappears twice. This is easier to see in slow motion, but it's still visible at normal speed. (00:04:27)
Back to School / Egg Story - S4-E8
Revealing mistake: Egg Story: When Arnold tells Helga, "I know you don't like me, and frankly, you're not my favorite person either," his mouth disappears twice. (00:14:51)
Gerald's Game / Fishing Trip - S5-E15
Revealing mistake: Gerald's Game: When Arnold and Gerald are playing The King Rules together, as Arnold says, "I'm not going to quit, Gerald," his mouth briefly disappears. (00:09:49)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Revealing mistake: Timberly Loves Arnold: When Lila tells Arnold that it's sweet that he is hanging out with Gerald's sister, the stripe on her shirt is layered over her gold button for one frame. (00:05:33)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Revealing mistake: Timberly Loves Arnold: When Lila says, "That is, if Arnold doesn't mind making it a threesome," her left eyelashes disappear for one frame. (00:05:50)
Stuck in a Tree / Rhonda Goes Broke - S5-E10
Revealing mistake: Rhonda Goes Broke: When Rhonda says, "I'm power walking. It's the healthiest way to get home," her mouth disappears four times. (00:21:42)
The Big Scoop / Harold's Kitty - S2-E3
Revealing mistake: Harold's Kitty: When Arnold kicks the ball during the kickball game, he starts running, and he is layered over Helga, even though he is supposed to be behind her. (00:12:20)
Helga's Boyfriend / Crush on Teacher - S2-E14
Revealing mistake: Helga's Boyfriend: When Arnold walks up to Helga to tell her that Stinky loves her, he asks if he can talk to her about something, and in the shot of Helga, there is a line at the bottom of the screen going through her legs, cutting them off. (00:08:04)
Operation Ruthless/The Vacant Lot - S1-E7
Revealing mistake: Operation Ruthless: When Helga and Phoebe are chasing Ruth in the bumper car, when Ruth's car stops and Helga looks back at her, Helga's right lower leg is incorrectly layered over the bumper car seat, and Phoebe's legs are colored black. (00:08:11)
Monkeyman! / Buses, Bikes and Subways - S5-E1
Revealing mistake: Buses, Bikes, and Subways: When Helga and Harold are riding the clown bike, a tall clown and two little clowns start chasing them. As the clowns are running, the left little clown is layered over the tall clown's right leg for a few frames, and the right little clown runs right through it. (00:17:39)
Summer Love (a.k.a. Beach Story) - S5-E9
Revealing mistake: When Helga is sitting on the boardwalk talking to her locket, as she starts to lay down, she is layered over part of the boardwalk that is in front of her. Her shadow is also layered over it. (00:12:24)
Monkeyman! / Buses, Bikes and Subways - S5-E1
Revealing mistake: Monkeyman!: When Arnold tells the kids that Monkeyman saved him, as he says, "He went after the two guys who were trying to mug me," he moves his right hand, and it's layered over Helga's hair. (00:01:25)
Revealing mistake: In Arnold's nightmare, when Bob points out that a stork is flying off their roof, his legs are incorrectly layered behind his cape. (00:12:50)
Full Moon / Student Teacher - S4-E1
Revealing mistake: Student Teacher: When Olga says, "But, nothing, baby sister!" before giving Helga detention, Rhonda and Brainy disappear for one frame. (00:17:17)
Full Moon / Student Teacher - S4-E1
Revealing mistake: Full Moon: When Harold tells Arnold, "Remember when I said you didn't have any guts because you wouldn't moon Principal Wartz?" his mouth briefly disappears. This is easier to see in slow motion but is still visible at normal speed. (00:11:16)
Phoebe Takes the Fall / The Pig War - S3-E16
Revealing mistake: Phoebe Takes the Fall: When Phoebe is in Helga's room helping her study for the tournament, as Helga says, "Well, let's call it a night," her left side hair is missing, then it appears mid-shot. (00:06:54)
Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Revealing mistake: Helga and the Nanny: When Helga tells the other kids that her nanny was fired, as she says, "Yeah, well my dad found his lucky belt under her bed this morning," her left-side hair disappears for one frame. (00:20:06)
Runaway Float / Partners - S2-E20
Revealing mistake: Runaway Float: When Arnold and Gerald are watching the parade, Arnold turns his head to look at the marching band. When he looks away from it, his left eye doesn't move, and it stays visible in his hair for the remainder of the shot. (00:07:51)
The Aptitude Test / Oskar Gets a Job - S3-E9
Revealing mistake: The test paper Eugene put back in Harold's folder is blank.
Suggested correction: The paper is not blank. Helga used a purple pen to fill in her paper, and Eugene put it in Harold's folder. The paper is filled with purple ink.
