Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Other mistake: Eugene, Eugene!: When the kids sing "Sunny Side Up" at the end, as they sing, "Who cares if the day is foggy and gray?", the crown of Lila's hat disappears for one frame. (00:22:46)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Other mistake: Timberly Loves Arnold: When Harold is leaving the field after the baseball game, he vanishes while on screen without fully leaving the frame. (00:06:15)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Other mistake: Eugene, Eugene!: After Phoebe and Helga walk into the auditorium, the shot fades to inside the auditorium. If you look at Mr. Leichliter in this shot, you will see that his body is missing. As a result, his head and scarf are floating in mid-air. (00:11:50)






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 ★